While looking up the history of kip, I realized that the information about its origins is rather scant. The noun and verb to kip in BrEng is often said when a person wishes to take a short sleep or a quick nap. It's a colloquial expression and sounds very post-war Britain to my ears. Surprisingly, Etymonline completely ignores the word, listing only kipper. Wiktionary on the other hand comes to the rescue:
1760–70, probably related to Danish kippe (“dive, hovel, cheap inn”) and Middle Low German kiffe (“hovel”). From the same distant Germanic root as cove.
Noun kip (plural kips)
(informal, chiefly UK) A place to sleep; a rooming house; a bed.
(informal, chiefly UK) Sleep, snooze, nap, forty winks, doze. "I’m just going for my afternoon kip." (informal, chiefly UK) A very untidy house or room. (informal, chiefly UK, dated) A brothel.
But thanks to a comment left by Janus Bahs Jacquet it seems the connection between kippe and kip is quite strained.
... but kippe (as a noun) is beyond vanishingly rare in Danish. It’s a marginally common verb, meaning ‘tilt’ or ‘lop’ (or ‘dip’ as in ‘dipping the flag’), but according to the dictionary, the noun and the verb are unrelated. The noun is allegedly the same as kipe ‘basket for carrying grain’. Supposedly, the shift from ‘basket’ to ‘hovel’ was helped along by Middle Low German kiffe ‘hut’, whence it was used in compounds to refer specifically to a real dive or a brothel, which is when English presumably borrowed (?) it. Quite a shaky etymology overall, I’d say
So on my trek to find the truth, I came across the Chinese-English Dictionary of the vernacular or spoken language of Amoy by Carstairs Douglas, printed in 1873, London. The language Amoy or otherwise known as Xiamenese, Xiamen or Hokkien dialect, I believe gives some insight as to how kip was loaned to the British English language to mean a short sleep or nap. It says
Kip [R. hasty; urgent; in extremity].
tioh-kip, in very great haste; not willing to wait a moment, as in some very urgent matter.
kip-kip, very swift, like the demon of thunder [...] said also figuratively of anything to be done in great haste.
kip-sio, a small thin flat-bottomed earthen kettle for warming things quickly.
Could it be that Dutch sailors adopted this expression? I am blissfully unaware of Danish maritime history but I seem to remember reading somewhere that the Dutch traded with the Chinese, was it the 13th century or later? This in turn reminds me of the Italian explorer Marco Polo and his tales in China in The Travels of Marco Polo or, in Italian Il Milione ("The Million"). But in Italian the letter K is a foreign letter and I can think of no Italian words beginning with ch = /k/ which are remotely related to the meaning of haste, urgency or velocity.
Could kip therefore be a Chinese loanword in the Danish or English language?