Familiar

1. Known to one, or generally known; commonplace.
2. Acquainted.
3. Intimate or friendly.
4. Inappropriately intimate or friendly.
5. Of or pertaining to a family; familial.

Synonyms

• (acquainted): acquainted
• (intimate, friendly): close, friendly, intimate, personal
• (inappropriately intimate or friendly): cheeky, fresh, impudent

Antonyms

• (known to one): unfamiliar, unknown
• (acquainted): unacquainted
• (intimate): cold, cool, distant, impersonal, standoffish, unfriendly