You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
Given a category and a set of five words, find the word from the set that does not belong (i.e. is the least relevant) with the other words in the category. Words are separated by commas.

Category: construction 
Words: excavator, crane, pelican, hoist, upraise
Solution: pelican
Why? A pelican is not related to construction because it is a type of bird.

New input: Category: employment activity 
Words: let go, fire, recruit, promote, earth
Solution:
earth