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.

[EX Q]: Category: measurement unit 
Words: ounce, foot, kilometer, milimeter, heel
[EX A]: heel

[EX Q]: Category: type of sandwich 
Words: open-faced, team, roll, doorstep, club
[EX A]: team

[EX Q]: Category: card games 
Words: tonic, slapjack, gin, spider, bridge
[EX A]:
tonic