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: digger, concrete pourer, crane, derrick, excavator
derrick

Category: emotional status 
Words: fret, emotional supports, output cord, angry, concerned
output cord

Category: animal 
Words: trap, sea turtle, shark, fish, dog

trap