TASK DEFINITION: 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.
PROBLEM: Category: employment activity 
Words: fire, hire, ground, pay, retire

SOLUTION: ground

PROBLEM: Category: geographical property 
Words: mountain, flat, hill, mansion, plain

SOLUTION: mansion

PROBLEM: Category: guitar part 
Words: inlays, concerned, fret, fingerpick, output cord

SOLUTION:
concerned