burner account
anonymous, cowardly
the one-line answer
A disposable anonymous account created to say things without accountability.
A burner account is created specifically to avoid accountability. You say what you want and the account disappears or is untraceable to you. Often associated with harassment or saying things you know would damage your reputation if said on your real account.
mainstream
Your coworker might use this word.
01 / in the wild
hear it move.
callout
he posts from a burner and thinks nobody knows who he is.
He uses an anonymous account to avoid accountability for his posts.