When a guy has inserted his penis into his partners vagina for the first time, but doesn’t cum. He is considered a half-virgin because he hasn't fully experienced sex.
I almost lost my virginity, but I just couldn't cum, at least now im only half-virgin.
Term for people who got first shot of a vaccine but were too lazy and/or moronic to get the second, or waited too long so the 2nd would no longer be effective