Dictionary

drop a dime en · VERB

See dime § Etymology 2

(idiomatic, slang) To make a telephone call.
(slang, with-on) To inform, to call the authorities (on).
- He was in the back for a few minutes. Turned out he was dropping a dime on Ralph.
- Near-synonyms: give [someone] up, give [someone] away; spill the beans, let the cat out of the bag
- We got a crowd of black, white customers, out-of-state license plates, what have you. Somebody gonna check that out. They gonna drop a dime on me, call 911. And you know with my jacket I can't go back to jail. 1995 September 13, Richard Price, Spike Lee, 00:27:05 from the start, in Clockers, spoken by Rodney Little (Delroy Lindo), 40 Acres and a Mule Filmworks; distributed by Universal Pictures:
- Who dropped a dime to that newspaper reporter, Your Honor? 2002 July 14, Rafael Alvarez, “One Arrest” (11:51 from the start), in The Wire, season 1, episode 7 (television production), spoken by Jimmy McNulty (Dominic West), via HBO:

Spelling	Features	Labels	Source
dropped a dime	Tense=Past, VerbForm=Part		lexicographic
dropped a dime	Tense=Past		lexicographic
drops a dime	Number=Sing, Person=3, Tense=Pres		lexicographic
dropping a dime	Tense=Pres, VerbForm=Part		lexicographic
drop a nickel		alternative	lexicographic