教练的严厉评价打击了他的自信心。

The coach's harsh comments deflated his confidence.

deflated 是动词 deflate 的过去式。deflate 由前缀 de-（表示"去除、减少"）和词根 flate（来自拉丁语 flare，意为"吹气"）组成，字面意思是"放气"。引申为"使泄气、打击（信心）"的意思。