For example, “flammable” and “inflammable” both describe an object that can easily catch on fire. I can also think of “ceased” and “deceased”, both of which can mean someone or something has been brought to an end.
edit: Some people are including words that can also mean its opposite (like sanction or table), those are cool too! The more weird words, the better!
The point was not that rent and lease are opposites of each other, but that both each contain opposite meanings.
Rent means both to grant possession of a thing in exchange for rent AND to take a thing and hold in an agreement to pay rent.
Lease means both to grant by lease and to hold under lease.
So, put another way: “rent” has two opposite definitions, and “lease” has two opposite definitions.
Not that rent/lease are opposites of each other.