I prefer wearing peep-toe heels in summer because they keep my feet cooler.

peep-toe 是由动词 peep（偷看、窥视）和名词 toe（脚趾）组成的复合形容词，字面意思是"能偷看到脚趾的"，用来描述鞋头部分露出脚趾的高跟鞋款式。