'time bomb' definitions:

Definition of 'time bomb'

(from WordNet)
noun
A problematic situation that will eventually become dangerous if not addressed; "India is a demographic time bomb"; "the refugee camp is a ticking bomb waiting to go off" [syn: time bomb, ticking bomb]
noun
A bomb that has a detonating mechanism that can be set to go off at a particular time [syn: time bomb, infernal machine]

Synonyms of 'time bomb'

From: Moby Thesaurus