He likes to wear his hair in a crew cut.

wear 的意思是"穿着、佩戴"，在这里引申为"保持某种发型"。 crew cut 指一种非常短的男士发型，头发整体长度一致，通常用推剪修剪，中文称为"平头"或"寸头"。 wear one's hair in a crew cut 表示"保持平头发型"。