One-of-a-kind and One-off

One-off and one-of-a-kind are semantically related. In some cases you can use "One-off" instead an adjective phrase "One-of-a-kind".

One-off adjective - Being the one or ones of a class with no other members.

One-of-a-kind and one-off are semantically related. Sometimes you can use "One-of-a-kind" instead an adjective phrase "One-off".