From Johnson's Dictionary: Myrmidon

myrmidon. Any rude ruffian; so named from the soldiers of Achilles.

(If you're interested in the Trojan War, this word isn't new to you. But it surprised me that it was apparently in currency during the 17th-18th centuries (probably 17th; Johnson refused to use books to find words that weren't at least (if memory serves) 50 years old)).