weyḱ-eyo-
“to keep conquering, prevailing”victory, convince, convict, evict
Iterative of *weyḱ- giving Latin vincere, English victory, convince, convict, evict, invincible.
Discussion
The PIE form *weyḱ-eyo- (to keep conquering, prevailing) is an iterative-intensive derivative of the root *weyḱ- (to fight, to conquer), formed with the *-eyo- suffix that expresses repeated or habitual action. The literal sense is "to be in the process of conquering" — victory not as a single event but as an ongoing state.
Latin vincere (to conquer, to prevail) is the primary reflex, with the expected nasal infix in the present stem (a morphological pattern shared with tangere, frangere, and other Latin verbs). From vincere and its past participle victus came an enormous English vocabulary: victory, victor, victorious, vanquish (via Old French vaincre from vincere), convince (to conquer thoroughly, hence to persuade completely), convict (to prove guilty, literally to conquer in argument), evict (to conquer out of, to expel by legal force), invincible (unconquerable), province (literally pro-vincere, a conquered territory administered on behalf of Rome), and Vincent (the conquering one, a personal name).
The semantic development from "conquer" to "prove/persuade" is visible in the Latin legal and rhetorical vocabulary. Convincere meant to refute conclusively — to win an argument as one wins a battle. This metaphor of argument-as-combat, so deeply embedded in English that we barely notice it (we "attack" positions, "defend" claims, "defeat" objections), has its roots in the PIE conceptual equation of physical and intellectual struggle.
Gothic weihan (to fight) and Old Norse vega (to fight, to slay) preserve the Germanic reflex with the original martial meaning undiluted. Old English wīgan (to fight) is attested primarily in compounds and derivatives. The Old Norse word survives in modern Scandinavian: Norwegian veie and Swedish väga, though the fighting sense has been largely displaced.
Sanskrit vijáyate (he conquers) and vijaya- (victory, conquest) continue the root in the Indo-Iranian branch. The personal name Vijaya (victorious) is one of the most common names in South Asian languages, appearing in the founding legend of Sri Lanka (King Vijaya) and throughout Hindu and Buddhist traditions.
Old Irish fichid (he fights) and Welsh gweithio (to work, to fight — the semantic overlap of "work" and "fight" is notable) provide Celtic attestation.
The derivational suffix *-eyo- is characteristic of PIE iterative stems — formations that express ongoing, repeated, or habitual action. Other examples include *bʰor-eyo- (to keep carrying) and *mon-eyo- (to keep thinking/remembering). The suffix survived into Latin as the first conjugation type (-āre), the most productive verb class in the language.