boxer, brawler, butter, defender, fencer, gamecock, gladiator, gouger, grappler, master, matman, mauler, pugilist, skirmisher, superior, swordsman, tough, victor, withstander, wrestler.
Your query has returned 300 words, which include anagrams of belligerent as well as other shorter words that can be made using the letters included in belligerent.
The words in this list can be used in games such as Scrabble, Words with Friends, Wordscapes and other similar games.