A wry or forced smile (often indicating embarrassment, awkwardness, or resignation); used as a noun or as the verb 'to give a wry smile'.
彼の説明を聞いて、私は苦笑してしまった。
Listening to his explanation, I couldn't help but give a wry smile.
その冗談にはみんな苦笑いを浮かべた。
Everyone gave a strained smile at that joke.
予想外のミスに対して上司は苦笑をもらした。
The boss gave a wry smile at the unexpected mistake.