the opposite sex
Collectively, the members of the other gender, typically the gender to which one is attacted. I still remember the torture of being in middle school, suddenly so fascinated by but at once terrified of the opposite sex. I don't understand this tendency we have right now to demonize the opposite sex as some kind of enemy in a made-up social war.
opposite sex
the other sex; (from the point of view of a female) males; (from the point of view of a male) females. (Also with member of, as in the example.) Ann is crazy about the opposite sex. Bill is very shy when he's introduced to the opposite sex. Do members of the opposite sex make you nervous?