Ambiguously gay duo.
They're ambiguously gay! 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. Fanservicethis character hardly bats an eye, but he seems quite ambiguously 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 gay sexuality is simply never made clear within the work. Yes, this character is Ambiguously Gay—they display much onscreen evidence of exclusive same-gender attraction, but nothing is ever explicitly confirmed one way or another.
The ambiguity can range all the way from from blink-and-you'll-miss-it implications to all-but-confirmed. This trope has taken slightly different forms throughout the past due to differences in censorship and what was permissible in the media. In many old films, characters were often given descriptions that may be perceived as code words for "gay".
In other cases where the censors may not have permitted any overt implications of homosexual attraction, creators would sometimes deliberately utilize stereotypical traits as a way of Getting Crap Past the Radar and implying a character's duo.
Mr. Pettibone
For example a male character might lispshow and have an interest in fashion and musicalshave no apparent interest in the opposite sex, and live gay a single-bedroom apartment with one of their "roommates". In modern sociological theory, these characters are described as being "queer-coded".
This particular permutation of Ambiguously Gay has largely become a Broken Trope in domestic media due to contemporary media being more open to depiction of explicitly gay characters, many of whom don't necessarily conform to stereotypes. However, it still lives on in some kinds of media aimed at international audiences, due to certain countries having more stringent anti-LGBT censorship than others.
As a result, modern instances of the trope are less likely to rely on stereotypes or code; common reasons for characters in newer works being considered Ambiguously Gay include a lack of interest in heterosexual relationships, overtly implied romantic or sexual interest in a character of the same gender, and In-Universe rumors about the character's sexuality.
Compare Hide Your Lesbianswherein the relationship between two characters is ambiguously gay. It's frequently combined with Word of Gayfor cases when the character's homosexuality remains deliberately ambiguous within the work itself but is declared elsewhere by a creator.
A closely related trope is Ambiguously Biwhich is similar to this trope but with bisexuality as opposed to homosexuality, and often involves a character who often shows explicit attraction towards at least one gender in canon. Compare and contrast with Homoerotic Subtextwhich is ambiguously same-gender characters who may or may not be attracted to each other, but nevertheless have gay moments which are often lampshaded by the work itself.
See also Pseudo-Romantic Friendship. Also duo and contrast Queer Establishing Momentfor when an Ambiguously Gay character graduates out of the "Ambiguously" part. Not to be confused with Ho Yaywhich is an Audience Reaction for fans interpreting any interactions between two characters of the same gender as homoerotic, whether or not it's deliberately gay within the text and regardless of what sexual orientation the characters may have in canon.
A No Recent Examples rule applies to this trope. Examples for episodic works shouldn't be added until end of season for the season introducing the ambiguity or after 3 monthsfor episodic works without seasons. This is to allow time for the story to develop the character and resolve ambiguity. There is no waiting time for non-episodic works.
No Real Life Examples, Please! It is ambiguously of our duo to speculate on the sexuality of real-life people, which is often far more complicated than in fiction.