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.

Q: sustainability, firm, amalgamated, combined, rigged

A: rigged
****
Q: group, clan, hamburger, club, bar

A: hamburger
****
Q: kind, down, descending, emotional, ashamed

A:
descending
****