People shouldn't try to pigeonhole others into convenient holes.
Bill has known Tom for many years but now Tom wants to start hanging out more with Bill, and Bill isn't sure they are very good friends.
Bill wants to decide if Tom is a good enough friend to hang out with.
Bill doesn't label Tom in any particular way and hangs out with him when he is not busy.
Bill decides that Tom is an acquaintance, not really a friend, and declines to hang out with him.
Tom and Bill find that they both enjoy life more thoroughly as a result of the increased social interaction.
Bill is hurt by Tom's refusal to hang out with him and Tom misses an opportunity to go out more often and socialize.