What it means
A subtweet is a post that's clearly about someone without ever naming them, so they might recognise themselves but you can always deny it. It's the passive-aggressive vague-post, all pointed shade and no @, leaving everyone to guess who it's aimed at. The whole art is being obvious enough to sting but slippery enough to deny.
Usage examples
"That subtweet about people who never text back was definitely aimed at me."
"Instead of just messaging her, she fired off a subtweet for the whole timeline to see."
"He swears that wasn't a subtweet, but everybody knew exactly who he was cooking."
"If you've got an issue with me, say it with chest instead of doing little subtweets at midnight."
Where it comes from
Subtweet came out of Twitter culture in the late 2000s and early 2010s. It builds from tweet with sub doing the hidden-message bit, meaning a post aimed at someone without naming them. People also linked it to subliminal tweet early on, but subtweet is the form that stuck and spread way past Twitter.
This expression also appears in
