A "yearncel" is a combination of "yearn" and "incel." It refers to men, who yearn for romantic or sexual relationships but find themselves involuntarily celibate, meaning they are unable to achieve such relationships despite wanting them.
The term "incel" is mostly about the frustration and resentment about their lack of romantic or sexual success. while as for the term "yearncel" it emphasizes the deep longing or yearning.
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi