"to catch (someone)," 1680s, probably a variant of dialectal nap "to seize, catch, lay hold of" (1670s, now surviving only in kidnap), which possibly is from Scandinavian (cf. Norwegian nappe, Swedish nappa "to catch, snatch;" Danish nappe "to pinch, pull"); reinforced by Middle English napand "grasping, greedy." Related: Nabbed; nabbing.
(also nabs) A police officer or detective (1950s+ Street gang)
To catch; seize; arrest; collar: The officers nabbed him around the corner (1686+)
[fr dialect nap as in kidnap, perhaps related to Swedish nappa, ''catch,'' or Danish nappe, ''pull''; probably related to nip; the noun sense is recorded in British criminal slang by 1813]