the.com/pseudonym

means A fictitious name a person uses instead of their real one — often to write, perform, or act under cover.

from From Greek pseudōnymos, 'under a false name' — pseudēs, 'false' or 'lying,' fused with onyma/onoma, 'name.' English borrowed it in the early 19th century, mostly for authors who wanted their words read without their name attached — same root family that gave us 'pseudo-' for anything counterfeit or so-called.