So why does washable mean unwashable?
Why does flammable mean the same as inflammable?
Why do you drive on a parkway and park in a driveway?
Does boned mean boned or unboned? Either way? Vice-versa?
The English language is so cockeyed.
Why does “lead” mean “conduct in a forward direction” and also “the element the Romans called Plumbum”?
In the spirit of your sets of opposites ... why does “cleave” mean “bond together” and “violently split apart”? ... English got the way it is because of a history of both conquering and being conquered. Romans conquered Western Europe. Scandinavians conquered England and parts of France. Latinized Scandinavians ... my amigos the Normans ... conquered England. England did the Industrial Revolution every which where.
It’s possible that there are language of the Indian subcontinent or of China that have a similar history, but I don’t know enough about them to say.