olemus
(1) viitsütikuga pomm; viitmiin: taimeriga detoneeritav lõhkesede
Wiktionary:
1. a bomb that has a mechanism such that detonation can be preset to a particular time
https://en.wikipedia.org/wiki/Time_bomb

(2) loogikapomm, mis käivitub ettemääratud ajal
Wiktionary:
2. (computing) a program designed to perform a destructive action at a certain date and/or time
https://en.wikipedia.org/wiki/Time_bomb_(software)

(3) piltlikult: olukord, mis ähvardab millegi tulevikus ilmneva halvaga
Wiktionary:
3. (figuratively) a situation that threatens to have disastrous consequences at some future time