pugnacious adj.

"disposition to fight, quarrelsomeness," c. 1600, from Latin pugnacitas "fondness for fighting," from pugnax (genitive pugnacis) "combative," from pugnare "to fight," especially with the fists, "contend against," from pugnus "a fist" (from PIE *pung-, nasalized form of root *peuk- "to prick").

also *peug-, Proto-Indo-European root meaning "to prick."

It forms all or part of: appoint; appointment; bung; compunction; contrapuntal; expugn; expunge; impugn; interpunction; oppugn; pink; poignant; point; pointe; pointillism; poniard; pounce; pugilism; pugilist; pugnacious; pugnacity; punch (n.1) "pointed tool for making holes or embossing;" punch (n.3) "a quick blow with the fist;" punch (v.) "to hit with the fist;" puncheon (n.2) "pointed tool for punching or piercing;" punctilio; punctilious; punctual; punctuate; punctuation; puncture; pungent; punty; Pygmy; repugn; repugnance; repugnant.

It is the hypothetical source of/evidence for its existence is provided by: Greek pyx "with clenched fist," pygme "fist, boxing," pyktes "boxer;" Latin pugnare "to fight," especially with the fists, pungere "to pierce, prick."