The most common and most likely answer to this crossword clue is the 10 letter word HOMOSEXUAL
I've seen this crossword clue in The Guardian
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More clues leading to the result HOMOSEXUAL
Buddy explains!
The straight part
We know that "Gay" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case gay = homosexual.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does HOMOSEXUAL mean?
HOMOSEXUAL noun- A person who is attracted solely or primarily to others of the same sex.
- (of a person or animal) Possessing sexual and/or emotional attraction towards members of the same sex. Examples being a male androphile or a female gynephile. (Sometimes used in the sense of sole/exclusive attraction.)
- (of a romantic or sexual act or relationship) Between two people of the same gender-area; gay.
- Intended for or used by homosexuals, as a nightclub, a bar, etc.