A bridegroom or simply groom, was a man who had just been or was about to be married.
While he and Kevin Riley were beginning to suffer from polywater intoxication in 2266, Hikaru Sulu remarked that, for reasons not yet known to him, he was "sweating like a bridegroom.", possibly attributing it to Psi 2000 or Joe Tormolen's death. Riley admitted the same was true of him, too. (TOS: "The Naked Time")