(uncountable) A state of being acquainted, or of having intimate, or more than slight or superficial, knowledge; personal knowledge gained by intercourse short of that of friendship or intimacy
(countable) A person or persons with whom one is acquainted.
Esimerkit
I know of the man; but have no acquaintance with him.
Contract no friendſhip, or even acquaintance, with a guileful man : he reſembles a coal, which when hot burneth the hand, and when cold blacketh it.