The trend of calling someone a Heather can be traced back to the song “Heather,” by Conan Gray. The song is about unrequited love. Here’s what Conan had to say about the song (via Apple Music):
“‘Heather’ is the song on the album that I always cry to. I think it’s the most honest recount of my love life at the moment. It’s about a girl named Heather — I think everyone has a Heather in their life. The person that I really, really liked was in love with Heather. They were not in love with me, and because of that, I f–king hated Heather. I hated Heather with all of my heart and soul.”
“I had no reason to hate Heather. Heather is a perfectly nice girl. She’s sweet and she’s pure and she smells like daisies—she’s perfect, but I hate her. It’s this humiliating thing to admit, but it’s just true.”
The song has been wildly popular on TikTok and is also the sound used in the viral Pinterest Trend. Essentially, people post videos using the song and saying they wish they were Heather (i.e., a very nice and attractive person), and then, more often than not, people comment on the video insisting that the person is Heather — in other words, they’re totally lovable and lovely. If someone calls you a Heather, they’re essentially saying that you’re a catch, even if you might not realize it yourself.
Source : https://www.distractify.com/p/what-does-heather-mean-on-tiktok