ready to fire a gun at the least provocation, regardless of the situation or probable consequences:
a trigger-happy hunter.
2.
heedless and foolhardy in matters of great importance and recklessly advocating action that can result in war:
Some called him a trigger-happy candidate.
3.
eager to point out the mistakes or shortcomings of others; aggressively or wantonly critical:
He's a trigger-happy editor with a nervous blue pencil.
Origin
1940-45
British Dictionary definitions for trigger happy
trigger-happy
adjective (informal)
1.
tending to resort to the use of firearms or violence irresponsibly
2.
tending to act rashly or without due consideration
Slang definitions & phrases for trigger happy
trigger-happy
adjective
Irresponsible in the use of firearms; eager to fire a gun
Idioms and Phrases with trigger happy
trigger happy
Inclined to act violently at the slightest provocation, as in They feared that the President was trigger happy and would send in troops at the drop of a hat. This expression alludes to being too eager to fire a gun. [ c. 1940 ]