1. Godan verb with 'su' ending, Transitive verb

   to clear; to make clear

   あの社長秘書はいつも澄ましている。

2. to be unruffled; to look unconcerned; to feign indifference

3. to look demure; to look prim; to put on airs

4. to strain (one's ears); to listen carefully

   see 耳を澄ますsee みみをすます

Also written 清ます【すます】sumasu