expugn v.

word-forming element, in English meaning usually "out of, from," but also "upwards, completely, deprive of, without," and "former;" from Latin ex "out of, from within; from which time, since; according to; in regard to," from PIE *eghs "out" (source also of Gaulish ex-, Old Irish ess-, Old Church Slavonic izu, Russian iz). In some cases also from Greek cognate ex, ek. PIE *eghs had comparative form *eks-tero and superlative *eks-t(e)r-emo-. Often reduced to e- before -b-, -d-, -g-, consonantal -i-, -l-, -m-, -n-, -v- (as in elude, emerge, evaporate, etc.).

"disposed to fight, quarrelsome," 1640s, a back-formation from pugnacity or else from Latin pugnacis, genitive of pugnax "combative, fond of fighting," from pugnare "to fight," especially with the fists, "contend against," from pugnus "a fist" (from PIE *pung-, nasalized form of root *peuk- "to prick"). Related: Pugnaciously; pugnaciousness.