Describes someone who is very popular with the opposite sex, often in a romantic or attractive sense. Colloquial and slightly playful.
See also: モテる
He's really popular at university.
I hear that new employee is really popular with the female staff.
Hiragana spelling; less common than katakana but still encountered.
Kanji spelling is rare and may be seen as playful or emphatic; usually written in kana.
Reduplication of the verb モテる (to be popular), with the repeated element adding emphasis. The exact derivation is uncertain, but it likely emerged as colloquial slang.