1.
one shot, one blow
A single shot (gun), punch, or strike.
2.
one try, in one attempt
Doing or achieving something in a single attempt.
一発 relates to single actions with impact.
COMMON COLLOCATIONS (Sense 1):
COMMON COLLOCATIONS (Sense 2):
COMMON EXPRESSIONS (Sense 3):
Usage
- 一発: in mahjong, a bonus for winning within one go-around of declaring riichi