Some words look like they should be opposites but really aren’t, I’ve noticed. They’re anti-antonyms. Examples: hottie and icy, inlaw and outlaw, onset and offset, upset and subset, postman and foreman, topping and bottoming, undertake and overtake, uppercut and undercut, expect and inspect, retail and detail, demote and remote. Forgive and forget are especially odd, since they’re almost synonyms.
Speaking of synonyms, other pairs of words look like they should be synonyms but aren’t. They’re pseudo-synonyms. Rocked and stoned, gasbag and airbag, iceman and snowman, footer and hoofer, pinpoint and needlepoint.