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。That president's secretary is always prim. to be unruffled; to look unconcerned; to feign indifference
to look demure; to look prim; to put on airs
to strain (one's ears); to listen carefully
Also written 清ます【すます】