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.

Example Input: Category: construction 
Words: excavator, steam roller, concrete pourer, swallow, crane
Example Output: swallow

Example Input: Category: consumer product 
Words: merchandise, happy, thing, content, service
Example Output: happy

Example Input: Category: corporate 
Words: synergy, sustainability, hard, alignment, firm
Example Output:
hard