[U] the quality of being average or not very good 平庸；普通；平常
His acting career started brilliantly, then sank into mediocrity.
他的演艺生涯开场时轰轰烈烈，然后就变得庸庸碌碌。
[C] a person who is not very good at sth 平庸之人；碌碌无为者
a brilliant leader, surrounded by mediocrities
周围全是些庸才的杰出领导