expression, noun
killer line; pick-up line; clincher
A phrase that captivates or persuades someone, often in romantic or persuasive contexts. Can be a smooth pick-up line or a decisive remark that wins someone over.
See also: 口説き文句 (くどきもんく)
彼はいつもバーで殺し文句を使っている。
He's always using pick-up lines at the bar.
その一言が殺し文句になって、彼女はついに承諾した。
That one phrase was the clincher, and she finally agreed.