贻笑大方 [- xiào dà fānɡ]expose oneself to ridicule; be laughed at by (the) experts; be laughed at by those who know; become a laughingstock of the learned people; give an expert cause for laughter; incur the ridicule of experts; laughed at by all respectable people; make laughingstock of oneself:
•¶ 我是个外行， 我说的话可能贻笑大方， 可我还是要说几句。 I'm a layman. What I'm going to say may expose myself to ridicule, yet I still want to say a few words.