Perfume, Scent
noun
A fragrance of water is a perfume.
こうすい
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
学校では香水が禁止されているにもかかわらず、その男子生徒はいつも甘い香りの香水を付けていて、教師たちには自然な脇の臭いだと言っていた。
Even though wearing perfume is banned at school, that guy always wears a fragrant perfume and he told the teachers that it was his natural armpit smell.