If "beggar" refers to a person who begs for money:
* Donor: Someone who gives money or other resources to others.
* Philanthropist: Someone who makes charitable donations.
* Benefactor: Someone who gives money or other help to a person or cause.
* Patron: Someone who supports a person or cause with money or other assistance.
If "beggar" refers to someone who is poor and needy:
* Wealthy: Someone who has a lot of money and possessions.
* Affluent: Someone who is rich and prosperous.
* Prosperous: Someone who is financially successful.
If "beggar" refers to someone who asks for something in a desperate or pleading manner:
* Demanding: Someone who makes strong requests or claims.
* Assertive: Someone who confidently expresses their needs and desires.
* Independent: Someone who is self-sufficient and does not rely on others.
The best antonym will depend on the specific context and the meaning of "beggar" that you are trying to convey.