pug·na·cious 
(pŭg-nāshəs)
(pŭg-nāshəs)adj.
Combative in nature. See Synonyms at belligerent.
[From Latin pugnāx, pugnāc-, from pugnāre, to fight, from pugnus, fist; see peuk- in the Appendix of Indo-European roots.]
pug·nacious·ly adv.
pug·nacious·ness, pug·naci·ty (-năsĭ-tē) n.