(v.) to support or endorse a romantic paring that is not canon in the work(s) in which they appear. The shipping of couples is often the purpose of many fanfiction stories. Used for characters in anime, manga, video games, tv shows, etc.
An unrealistic relationship that you love so much but causes you so much pain and misery forcing you to scream "MY FEELS!" while sliding out of your chair because it never comes true even though it's so obvious it should.