Cuff word origin

First, there is no necessary relationship between wearing a cuff and cuffing someone.

The Oxford English Dictionary says this about "cuff, n.1" (the clothing part):

Middle English coffe, cuffe, of uncertain origin. The word has some similarity of form to Middle Latin cuphia , cuffia , in Old English cuffie , cap, head-covering, French coiffe , coif n.; but no connection of sense appears.

Aside from having a similar form, the etymology here is inconclusive. The earliest uses in English (from 14th and 15th centuries) refer to a mitten or glove, with the sleeve-meaning appearing in the early 16th century. Here is a helpful quote showing the earlier use:

c1440 Promptorium Parvulorum 106 Cuffe, glove, or meteyne, mitta (J. ciroteca).

Attestations in the 16th century and afterward correspond to a fore-sleeve:

1522 in J. Raine Testamenta Eboracensia (1884) V. 154 My velvett jacket, to make his childer patlettes (i.e., neck garments) and cuyffes.

1594 T. Nashe Vnfortunate Traveller sig. C4 Cleane shirts and cuffes.

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The hand-blow meaning is in "cuff, n.2" and "cuff, v.1," and the etymology appears just as uncertain and unrelated:

Of uncertain origin: compare German Rogues' cant kuffen to thrash (‘perhaps of Hebraic origin’, Sievers); also Swedish kuffa to thrust, push.

This meaning is first attested in the early 16th century as well:

1530 J. Palsgrave Lesclarcissement 502/2 I cuffe one, I pomell hym about the heed, Je torche.

Pummelling (also in the quote as pomell) is derived from the name of an object that can be used in the action, a pommel, so it is certainly possible that cuffing is related to the name of an object that can be used in the action, a cuff (mitten or glove or sleeve; something covering the hand). There is just no firm example connecting the two, let alone a firm connection between the English cuffs and similar forms in other languages. So the similarity to Arabic could be a coincidence, or there could be an undiscovered connection via (for example) the use of German Rogues' cant.

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