He tried to impress his boss with some self-deprecating comments about his own mistakes.

self-deprecating 是由 self（自己）和 deprecating（贬低的）组成的复合形容词。deprecating 来自动词 deprecate，意思是"表示不赞成、贬低"。 self-deprecating 指"自我贬低的、自嘲的"，通常用来形容通过幽默地贬低自己来显得谦虚或讨人喜欢的说话方式。