- with reference to; concerning关于; 与…有关的：
she remarked apropos of the initiative, 'It's not going to stop the abuse'.
她就这一倡议发表意见时说“这无法阻止虐待现象”。
sentence adverb(apropos of nothing)
- used to state a speaker's belief that someone's comments or acts are unrelated to any previous discussion or situation无缘无故地; （与当前谈论或情况） 没有任何联系地：
Isabel kept smiling apropos of nothing.
伊莎贝尔无缘无故地微笑着。
predic.
- very appropriate to a particular situation与某一情景相配的, 适合的：
the song feels apropos to a midnight jaunt.
这首曲子和午夜小游很相配。
词源
mid 17th cent.: from French à propos '(with regard) to (this) purpose'.