由于经济不景气，公司决定裁员20%以节省开支。

The firm retrenched 20% of its workforce to cut costs during the downturn.

retrenched 是动词 retrench 的过去式。retrench 由前缀 re-（表示"重新、再次"）和 trench（原意为"壕沟"，引申为"削减"）组成，字面意思是"重新削减"，特指在经济困难时期通过裁员来缩减开支。