expression, godan verb (-u)
laugh scornfully; sneer at
Idiomatic expression describing a contemptuous laugh directed at someone, often with a nuance of looking down on them.
彼は私の提案を鼻先で笑った。
He sneered at my proposal.
そんな考えは鼻先で笑われる
An idea like that will just be laughed at scornfully.