ready and able to resort to force or violence; "pugnacious spirits lamented that there was so little prospect of an exhilarating disturbance"- Herman Melville; "they were rough and determined fighting men"
Someone who is pugnacious is always ready to quarrel or start a fight. The President was in a pugnacious mood when he spoke to journalists about the rebellion. very eager to argue or fight with people (pugnax, from pugnare )