Fan Casting Ambiguously Gay in Sort by Tropes

Perhaps you have a male character who is visibly touch-feely towards another male character, while being similarly open in rejecting the advances of any female characters who come his way. Or when the other male characters ogle the resident Ms. Fanservice, this character hardly bats an eye, but he seems quite interested in what the Walking Shirtless Scene is doing. Other characters in the work may even question exactly which way this character swings, but never get an answer. The character's sexuality is simply never made clear within the work.