Definition of gay adjective from the Oxford Advanced Learner's Dictionary

gay

adjective
ɡeɪ
 
; ɡeɪ
 
 
1 (of people, especially men) sexually attracted to people of the same sex
Synonym
homosexual
gay menI didn't know he was gay.Is she gay?
Opposite
straight
2 [only before noun] connected with people who are gaya gay club/barthe lesbian and gay community3 [not before noun] (slang, disapproving, sometimes offensive) (used especially by young people) boring and not fashionable or attractiveShe didn't like the ringtone—said it was gay.That is so gay!He likes skiing but thinks snowboarding is gay.4 gayer, gayest (old-fashioned) happy and full of fungay laughterShe felt lighthearted and gay.5 (old-fashioned) brightly colouredThe garden was gay with red geraniums. see also gaiety see also gaily
Idioms

with gay abandon

without thinking about the results or effects of a particular action