trigger-happy
adjective uk/ˈtrɪɡ.əˌhæp.i/ us/ˈtrɪɡ.ɚˌhæp.i/
informal爱乱开枪的，动辄开枪的
Someone who is trigger-happy often uses his or her gun, shooting with very little reason.
Some have accused the police of being trigger-happy. 一些人指责警方开枪草率。
disapproving好斗的，爱动武的
ready to use violence or force immediately, without careful thought
He deplored the behaviour of his trigger-happy, hot-headed son. 他谴责自己头脑发热爱动武的儿子的行为。