Late 16th century (as a verb): probably frequentative, from the base of poke² and pocket (suggesting the formation of small purse-like gatherings).

• pocket from Middle English:

  The first sense recorded for pocket was a ‘bag, sack’. It comes from Anglo-Norman French poket(e), a little poke or pouch (see pig). This also lies behind poach. Poaching eggs and poaching game may seem vastly different activities, but they are both probably connected with the Old French word pochier or French pocher, ‘to enclose in a bag’. When you poach an egg you can think of the white of the egg as forming a pocket or bag for the yolk to cook in. The second poach first meant ‘to push together in a heap’, and acquired the ‘steal game’ sense in the early 17th century. The connection with the source word comes from the pocket or bag into which a poacher would stuff his ill-gotten gains. Pucker (late 16th century) is probably from the same source, with the little gatherings being seen as small pockets.