Formal/literary. Almost always appears in the negative (不便置喙 'not appropriate to comment', 无从置喙 'no grounds to comment', 无权置喙 'no right to comment') as a polite way of saying 'not my place to speak'.
memory
喙 (huì) is the beak of a bird. 置喙 literally means 'to insert one's beak' — like the English idiom 'to stick one's beak in.'
