滥竽充数làn yú chōng shù
[pass oneself off as one of the players in an ensemble;hold a post without adequate qualifications; simply to make up the number] 不会吹竽的人,混在吹竽的乐队里充数(故事见《韩非子·内储说上》)。比喻没有真才实学的人混在行家里面充数,或是以次货充好货。也用作自谦之词
若只靠才气,摭些陈言,便不好滥竽充数了。——清· 文康《儿女英雄传》