I've used doolally since I was a child, but I'd rarely heard the tap version until a few years ago in the company of several Welsh people (who all agreed the two-word version was their "standard").

They said it referred to insanity caused by contaminated tap water in Deolali (lead?, cadmium?).

But I've now discovered Wikipedia says...

"Doolally", originally "doolally tap", meaning to 'lose one′s mind', derived from the boredom felt at the Deolali British Army transit camp. 'Tap' may be derived from the Sanskrit word 'tapa' meaning 'heat' or 'fever'. It is also just conceivable that it derives from the Welsh word 'twp', meaning 'stultified', 'unable to reason sensibly'.

Can anyone either corroborate or refute any of these suggested etymologies?

  • It is all new to me. I had never considered the origin of the term though I have used it many times myself. I have never heard the 'tap' version. – WS2 May 31 '14 at 21:23
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    Interesting, that. I’ve heard both (though neither more than perhaps a dozen times, so I have no idea which I’ve heard more), and also just ‘tap’ on its own in the same sense. I never gave the etymology a second thought—I always just assumed that doolally is merely phonaesthetic and tap refers to tapping your temple or forehead to indicate that someone is bonkers! – Janus Bahs Jacquet May 31 '14 at 23:46
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    Also, one must presume that if tap is indeed from Welsh twp (which seems rather implausible to begin with—the vowel change alone would be highly irregular), then doolally almost has to have a different origin, too. No one in their right mind would add a Welsh word to the name of an Indian city to make an English term: the two source languages are just too far apart, but socially and geographically. – Janus Bahs Jacquet Jun 1 '14 at 0:09
  • (Damn typos. That was supposed to say “both socially and geographically” in my previous comment.) – Janus Bahs Jacquet Jun 2 '14 at 12:29
  • @Janus: Reading your comments yesterday was pretty much sufficient to convince me tap here didn't come from Welsh. But the absolute clincher was to discover the relevant definition in OED, with a citation from long before the doolally tap collocation. – FumbleFingers Jun 2 '14 at 12:35

Doolally comes from British army slang, originating when Deolali was a British army transit camp in India.

Doolally tap meant being mad, crazy or literally, suffering from camp fever. Tap in English is malarial fever, from the Hindi for fever.

The Madness at Deolali (Journal of the Royal Army Medical Corps) by Major NA Martin begins:

The slang word ‘doolally’ or ‘doolali’ is used to describe someone who is ‘out of one’s mind’ or ‘crazy’. It is a derivation of ‘doolali-tap’ and originates from the latter part of the nineteenth century.The first part of this phrase is derived from the name of a small military town in the Indian state of Maharashtra called Deolali. The second part is a Hindustani word for fever, often ascribed to malaria, although in Sanskrit, ‘tapa’ means simply heat or torment. Taken literally, it is best translated as ‘camp fever’. By the time of the Second World War, the term had been shortened to ‘doolally’.

A mixture of boredom, syphilis, venereal diseases, heat, mosquitoes, fever, malaria, sand fleas contributed to misery at the camp.

He concludes:

Frank Richards wrote, `The well known saying among soldiers when speaking of a man who does queer things, "Oh, he's got the Doolally tap, " originated, I think, in the peculiar way men behaved owing to the boredom of that camp'(2). While this may have been true at times, the reason that Deolali became synonymous with mental illness has more to do with the limitations imposed on troop movements by the seasons, the debilitating effect of the summer climate, alcoholism, venereal diseases, malaria, and the difficulties of treating mental illness in the colonies.

The OED's first recorded use is in 1925 but I found some 1916 examples.

A booklet titled The Way They Have in the Army (1916) by Thomas O'Toole has a chapter on on Tommy's Private Language:

Doolally Tap. When a soldier becomes mentally unbalanced, he is said to have received the " Doolally Tap." " Doolally " is a corruption of the name of an Indian town, Deolali.

The booklet and quoted in Australian newspapers: the Brunswick and Coburg Leader of Friday 12 May 1916 and The Australasian of the next day.

  • I'm going to plump for this answer, mainly because you've explicitly mentioned that tap in English is malarial fever. Although you haven't posted an online dictionary link confirming that, it was enough to nudge me to check OED myself. And that definition is indeed listed, with first citation 1882 - over 40 years before their first citation for doolally tap. So I'm now fully convinced those Welsh folk were simply wrong. – FumbleFingers Jun 2 '14 at 12:30
  • I've sent the antedatings to the OED. – Hugo Jun 2 '14 at 12:34
  • They will be glad of it, I'm sure. But even if it checks out, we're still talking about tap = malarial fever having been recorded decades earlier than Doolally tap. – FumbleFingers Jun 2 '14 at 12:38
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    Yes. There's a whole raft of [place] [word-for-fever] names, like Malta dog, Hong Kong dog, Ceylon sore mouth, Aztec two-step, Greek gallop, Rome runs, Tokyo trots, from soldiers and sailors getting sick in hot places (english.stackexchange.com/a/50805/9001). This sounds like originally just another variant, that's then changed meanings and lost the tap. – Hugo Jun 2 '14 at 13:56

According to the Etymonline Dictionary the original expression actually was doolally tap:

  • Doolally comes from the name of Deolai, a location near Bombay where the BritishnArmy had a camp.

  • Tap seems to derive from a local word meaning fever. The 'fever' in question refers to the impatience of soldiers to go back home after their enlistments had expired.

Doolally (adj.)

"insane, eccentric," British slang, by 1917 in the armed services and in full doolally tap (with Urdu word for "fever"), from Deolali, near Bombay, India, which was a military camp (established 1861) with a large barracks and a chief staging point for British troops on their way to or from India; the reference is to men whose enlistments had expired who waited there impatiently for transport home.


It's English army slang

Doolally Tap -when a soldier becomes mentally unbalanced he is said to have received the “Doolally Tap.” “Doolally” is a corruption of the name of an Indian town, Deolali. -Rhymes of the rookies . Christian, W. E.

& a fiction reference from Champion road [1950]that uses 'doolally' as a synonym for crazy:

"He's not behaving more than twenty-four!" I snapped before there was time to check myself, and then, seeing the expression on her face: "She's nought a pound, Janet, not a patch on you, not fit to lick your boots. Unless he's doolally he'll come back to you all right. Chaps only go after women like that for one thing." -

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