The phrase suggests the subject is getting so angry they're about to pull their hair out in exasperation, and should calm down instead. I found in print as early as 1879 and in an 1889 dictionary. Correspondence in the 1902 Victorian version of Stack Exchange says it was heard as early as 1853 and gives some possible etymologies.
The Concise New Partridge Dictionary of Slang and Unconventional English (2008) by Eric Partridge, Tom Dalzell and Terry Victor says:
keep your hair on! don't get upset! NEW ZEALAND, 1984
keep your shirt on! calm down!, relax!, compose yourself! UK, 1854
Passing English of the Victorian Era (1909) by J. Redding Ware:
Slang and Its Analogues Past and Present (1890) by John S. Farmer and W.E. Henley gives some variants:
On the same page they give to raise (or lift) hair, an American phrase meaning to scalp, and figuratively to defeat; and to keep one's hair is to escape danger. This may or may not be related.
A Dictionary of Slang, Jargon & Cant (1889) by Albert Barrère and Charles G. Leland is briefer:
However, it can be found much earlier in New Zealand's Observer newspaper (Volume 5, Issue 114, 18 November 1882, Page 153):
And slightly earlier in the South Australian Register (Adelaide, SA, Saturday 18 October 1879, p6), itself quoting The Glasgow Weekly Mail of August 18:
An hour's sail in a crowded
tugboat lands the passengers at Port Adelaide
where there ensues a wild scramble for luggage,
some of it having to be fished out of the water,
and a wordy combat with porters and railway
servants, who, should you get excited, coolly tell
you to 'Keep your hair on.'
Notes & Queries
Finally, the phrase is discussed at length in several 1902 editions of Notes and Queries (aka the Victorian Stack Exchange).
Notes and Queries (Page 335, 1902)
"Keep your hair on" (9th S. ix. 184).— My earliest recollection of this saying traces it no further back than the fall of 1871. At the Lord Mayor's Show in 1869 it was not heard in the streets. On Thanksgiving Day, February, 1872, it became a ...
... and the even worse crush at the illuminations, people were sometimes hard put to it to "keep in their rag." But then, as since, the customary reply from the good-tempered sort (of whom there are numbers in the world), when told to "keep their hair on," was "Haven't lost it yet." Some few years ago Lord Goschen said, in one of his public speeches that many of the slang or "cant" words in popular use originated in the schools and colleges of this country. He instanced "bloke" and "mug" ("mugster"). To show that "keep your hair on" had probably a likewise collegiate (or academic) origin, I should like to quote a few lines from Barrère's 'Argot and Slang: a New French and English Dictionary Words,' 1887 :—
"The English public schools, but especially the military establishments, seem to be not unimportant manufacturing centres for slang. Only a small proportion, however, of the expressions coined there appear to have been adopted by the general slang-talking public, as most are local terms, and can only be used at their own birthplace.....At Harrow.....a man who is vexed or angry 'loses his shirt' or his 'hair'; at Shrewsbury he is 'in a swot'; and at Winchester 'front.'”
HERBERT B. CLAYTON.
39, Renfrew Road, Lower Kennington Lane.
More than twenty years ago I was coming down one of the poorer streets of Hull and met a boy going to school smoking. I vainly tried to snatch the pipe out of his mouth. When the lad had got a safe distance from me he lifted his right hand to his nose, extended his fingers fan-like, and called out to me, "Keep your 'air on." I am able to fix the period in my mind, as I well remember the house in which I then lived.
Royal Institution, Hull.
I certainly recollect hearing this phrase used in the sense of "Don't be too excited" as far back as 1853, and have no doubt it was then well established.
E. F. D. C.
No doubt the slang sense illustrated in 'N.E.D.' is distinct from the literal meaning in Holcroft. But the underlying thought which gave rise to the expression in 1799 must surely have led directly to the slang sense long before 1883. A man is bidden to "keep his hair on "—i.e., not to allow himself to be ruffled by the storm of a sudden passion. The thought, which is exaggeration of fact in the one case, becomes metaphorical in the other, but the thought is the same.
W. C. B.
Another Notes and Queries (9th S. X. July 12, 1902, page 33):
"KEEP YOUR HAIR ON " (9 th S. ix. 184, 335).
Referring to the quotation from Barrère
by MR. CLAYTON, I heard a janitor of a
gymnasium complain of unsuccessful remon-
strance with intruders in these terms : "I
spoke to them about it, but they began to
get a bit shirty, so I had to fetch Mr. ------
[his superior officer] to talk to them." A
schoolfellow said once to me : "You are
swotting for top place" : an equivalent for
sweat or grind, no doubt.
FRANCIS P. MARCHANT.
This expression is common or is frequently
heard in Gloucestershire. Its origin is
supposed to be coeval with wigs or the wig
period. Irascible and aged gentlemen, "when
mad with passion," have been known not
only to curse and swear, but to tear their
wigs from their heads, and to trample them
under their feet, or to throw them into the
fire. Very often when I have manifested
symptoms of anger I have been admonished
by country fellows, "Kip thee yar on,
maystur !" This expression is synonymous
with keep your temper, or don't get into a
rage. Whenever I have heard the expression,
I have invariably associated it with the old
country squire who got into a thundering
rage and threw his wig off his bald head
and trampled it under his feet. Some-
times a similar expression or mandate is
used, "Kip the wig on, ould mon." I have
frequently heard old country farmers and
farm labourers say, "Daz my wig!" or "Dash
my wig if I wool," or "I dooes." In the old
days, if a man wished in his passion to be
emphatic, he threw off his wig.
H. Y. J. TAYLOR.
It is surprising to hear that this catch-
phrase was in use so early as 1853. Since
this is the case, is it not probable that it
existed even much earlier, that it may indeed
be traced to the latter half of the eighteenth
century, which saw a serious change of fashion
in the disuse of the peruke and the return to
the custom of wearing one's natural hair? 'I
strongly suspect that the phrase has some
relation in its origin to that of "Wigs on
the green," for there must be an unusual
difficulty, where there are "Wigs on the
green," (see 9th S. iii. 492), in "keeping one's
J. HOLDEN MACMICHAEL.
I remember in 1885, when I was an articled
clerk in Derbyshire, hearing a discussion
between a solicitor and a farmer in a room
of the comfortable old hostelry which forms
part of the Derby Law Courts. The farmer
was endeavouring to end a misunderstanding
which had arisen by saying, in reference to
some prior dispute between them, "That
was where you got your hair off," a phrase
he repeated several times, to the great
annoyance of the solicitor, who happened at
the same time to be rather young, very bald,
and extremely irascible.
JOHN HOBSON MATTHEWS.
Town Hall, Cardiff.
At the latter reference a passage is quoted
from Barrère's 'Argot and Slang.' The last
word of this quotation ought, I suspect, to
have been frout, and not "front."
A later N&Q (9th S. X. Aug. 23, 1902):
"KEEP YOUR HAIR ON" (9 th S. ix. 184, 335;
x. 33). A propos of MR. MARCHANT'S allusion
to the word "shirty" 'as a slang expression
for loss of temper, I overheard in the streets,
on the very day of your last issue, a similar
slang word. Two "vulgar boys," but by no
means "little vulgar boys," were talking, and
one of them said, "He fairly got my rag
out," his rag being presumably his shirt.
Probably the expression "to have (or get)
one's shirt out " has arisen, says Dr. Lentz-
ner in his 'Dict. of Australian Slang,' from
the shirt working out between the breeches
and waistcoat during a struggle. In Surrey
"shirty" means short-tempered, irritable.
As regards "rag" meaning " shirt," a soldier's
slang for the monthly inspection of kit--when
all the necessaries, shirts, socks, and under-
clothing, are displayed--is "rag-fair." With
regard to "swot" in the sense in which it is
used among students, the word is a very
ancient form of "sweat," and is employed as
an army term for mathematics, probably in
allusion to the hard work of an examination.
It is said to have originated in the broad
Scotch pronunciation by Dr. Wallace, one
of the professors at the Royal Military Col-
lege, Sandhurst, and to have afterwards
been fashionable at the universities. It is
not necessary, however, to go to Scotland for
this pronunciation of the word, for "swat"
is still in use in Staffordshire, and in C. H.
Poole's 'Staffordshire Glossary' Chaucer's
'Rime of Sir Thopas' is quoted:-
His fair stede in his pricking
Again, in Percy's 'Reliques,' i. 25:-
They swopede together whille
that they swotte.
The sweating sickness was called the "swatt"
(see Archcoeologia, xxxviii. 107).
J. HOLDEN MACMICHAEL.
In 'Epistolae Ho-Elianae' (eleventh edition,
p. 476) it is stated that, aforetime in France,
"Il a perdu ses cheveux" meant "he has lost
"For in the first Race of Kings there was a Law
called La loy de la Cheveleure, whereby it was
lawful for the Nobless only to wear long Hair, and
if any of them had committed some foul and ignoble
Act, they used to be condemned to have their long
Hair to be cut off as a Mark of Ignominy."
The modern meaning of the phrase "keep
your hair on" is, however, probably that
attached to it by your correspondents.
This expression has been common in Shrop-
shire for at least twenty-five years, and
probably much longer. "Don't get your
shirt out" was a frequent injunction when I
was at school. Like MR. MARCHANT'S friend,
we employed the verb to swot. Boys who
worked hard for examinations were dubbed
"swots," a term of contemptuous reproach.
[We supposed "getting the shirt out" meant
taking off the coat for the purpose of fighting and
so displaying the shirt.]