Having a quarrelsome or combative nature: Truculent. (Merriam – Webster)
Inclined to quarrel or fight readily; quarrelsome; belligerent; combative. (Dictionary.com)
Wanting to start an argument or fight, or expressing an argument or opinion very forcefully. (Cambridge Dictionary)
Someone who is pugnacious is always ready to quarrel or start a fight. (Collins Dictionary)
Eager or quick to argue, quarrel, or fight. (Oxford Dictionaries)
Determined, pugnacious fighter –The Whiting.
Why the pugnacious A-10 is flying maritime patrols over the South China Sea.