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]: fearful, content, substance, program, thing
[A]: fearful


[Q]: angular momentum, fat, calcium, brittleness, ugly
[A]: calcium


[Q]: wrestle, mice, cat, sea turtle, fish
[A]:
wrestle