To make fun of someone; to ridicule or mock someone (transitive verb).
子供たちが彼の奇妙な服装をあざ笑った。
The children mocked his strange outfit.
匿名の書き込みで彼女をあざ笑う人がいた。
There were people mocking her in anonymous posts.
人の失敗をあざ笑うのはやめなさい。
Stop making fun of other people's mistakes.