Nab
late 17th century (also as napp ; compare with kidnap): of unknown origin.
wiktionary
From dialectal nap(“to seize, lay hold of”), probably of North Germanic origin, from Old Swedish nappa(“to pluck, pinch”).
Related to Danish nappe(“to tweak, snatch at, catch, seize”), Swedish nappa(“to take, grab, pinch”), Norwegian nappe(“to pluck”).
Compare knap, knop, knob.
etymonline
nab (v.)
"to catch (someone) by a sudden grasp, seize suddenly," 1680s, probably a variant of dialectal nap "to seize, catch, lay hold of" (1670s, now surviving only in kidnap), which possibly is from Scandinavian (compare Norwegian nappe, Swedish nappa "to catch, snatch;" Danish nappe "to pinch, pull"); reinforced by Middle English napand "grasping, greedy." Related: Nabbed; nabbing. Nabbing-cull was old slang for "constable," and Farmer and Henley ("Slang and Its Analogues") has "TO NAB THE STIFLES = to be hanged."
