Provenance — where it came from
Around the year 2000, young women’s magazines and street slang produced a new word for a good-looking man: イケメン (ikemen). The first half is clear — イケてる (iketeru), slang for “looking good,” “cool.” The second half is where the word gets clever.
Men can be read two ways. It might be 面 (men), a Japanese word for “face” — so, “a good-looking face.” Or it might simply be the English word “men.” Both readings work. Both were probably intended by somebody. The word carries a Japanese etymology and an English one in the same two syllables, and has never been forced to pick.
Older words for “handsome” — 二枚目 (nimaime, from kabuki theater billing), ハンサム itself — sounded dated by comparison, and ikemen replaced them in daily speech within a few years. It settled in so completely that it stopped feeling like slang at all: a rare case of a street word winning a permanent job.
Field notes — how it’s used
駅前のカフェの店員、イケメンだよ
ekimae no kafe no ten'in, ikemen da yo
“The guy at the station café is an ikemen.” Intelligence travels fast.