used to describe something that is not as great in size, amount, or importance as something else

A lesser man (= a man who was not as strong or brave) might have given up at that point. 那时候稍微软弱一点的人就可能会放弃。

The charge of murder was altered to the lesser (= less serious) charge of manslaughter. 谋杀的指控被改成了较轻的过失杀人的罪名。

Ethiopia and, to a lesser extent/degree, Kenya will be badly affected by the drought. 埃塞俄比亚将受到干旱的严重影响，其次是肯尼亚。