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.
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Question: Category: corporate 
Words: unyielding, concerted, firm, combined, united

Answer: unyielding


Question: Category: boats 
Words: chips, crew, bow, deck, bridge

Answer: chips


Question: Category: bird 
Words: digger, heron, crane, mallet, sandpiper

Answer:
digger