a person you know well and regard with affection and trust

• he was my best friend at the university

• friend

an associate who provides cooperation or assistance

• he's a good ally in fight

• ally
• friend

a person with whom you are acquainted

• I have trouble remembering the names of all my acquaintances
• we are friends of the family

• acquaintance
• friend

a person who backs a politician or a team etc.

• all their supporters came out for the game
• they are friends of the library

• supporter
• protagonist
• champion
• admirer
• booster
• friend

a member of the Religious Society of Friends founded by George Fox (the Friends have never called themselves Quakers)

• Friend
• Quaker