General terms:
* Plagiarist: This is the most accurate if the person is directly copying others' work and claiming it as their own.
* Imposter: This term implies someone falsely presenting themselves as something they are not, including taking credit for others' work.
* Fraud: This term is more serious and implies a deliberate attempt to deceive others for personal gain.
* Self-promoter: This term is less accusatory but suggests someone is overly focused on promoting their own ideas, even at the expense of others.
* Egotist: This term suggests someone with an inflated sense of self-importance who believes their ideas are always the best.
More specific terms:
* Idea thief: This term is informal but accurately describes someone who steals ideas from others.
* Braggart: This term suggests someone who boasts about their ideas, even if they are not original.
* Phony: This term is a bit harsh but suggests someone who is insincere and not genuine.
The best term to use will depend on the specific situation and the severity of the behavior.