Words evolve - especially 'gay' .
Generalized pejorative use
When used with a derisive attitude (e.g., "that was so gay"), the word gay is pejorative. While retaining its other meanings, its use among young people as a general term of disparagement is common.[6][40] This pejorative usage has its origins in the late 1970s, with the word gaining a pejorative sense by association with the previous meaning: homosexuality was seen as inferior or undesirable.[41] Beginning in the 1980s, and especially in the late 1990s, the usage as a generic insult became common among young people.[6]
gay
/ɡeɪ/
adjective
adjective: gay; comparative adjective: gayer; superlative adjective: gayest
1.
(of a person) homosexual (used especially of a man).
"the city's gay and lesbian people"
relating to or used by homosexuals.
"a gay bar"
2.
dated
light-hearted and carefree.
"Nan had a gay disposition and a very pretty face"
synonyms: cheerful, cheery, merry, jolly, light-hearted, mirthful, jovial, glad, happy, bright, in good spirits, in high spirits, joyful, elated, exuberant, animated, lively, sprightly, vivacious, buoyant, bouncy, bubbly, perky, effervescent, playful, frolicsome; More
informalchirpy, on top of the world, as happy as a sandboy;
informalas happy as a clam
"her children all looked chubby and gay"
antonyms: gloomy
brightly coloured; showy.
"a gay profusion of purple and pink sweet peas"
synonyms: bright, brightly coloured, vivid, brilliant, rich, vibrant; More
richly coloured, many-coloured, multicoloured;
flamboyant, gaudy
"the windows sported gay checked curtains"
antonyms: drab
3.
informal•offensive
foolish, stupid, or unimpressive.
"he thinks the obsession with celebrity is totally gay"