Given a set of five words, generate the word from the set that does not belong (i.e. is the least relevant) with the other words. Words are separated by commas.

Let me give you an example: excavator, crane, pelican, hoist, upraise
The answer to this example can be: pelican
Here is why: The common category here are words related to construction. A pelican is not related to construction because it is a type of bird.

OK. solve this:
fair, make the grade, ok, mild, endure
Answer:
ok