mid-15c., "the breaking of an agreement," from Old French infraction (13c.) and directly from Latin infractionem (nominative infractio) "a breaking, weakening," noun of action from past participle stem of infringere "to damage, break off, break, bruise," from in- "in" (from PIE root *en "in") + frangere "to break" (from PIE root *bhreg- "to break"). The verb infract (1560s) is archaic.
infortunate
infotainment
infra
infra-
infra dig.
infraction
infralapsarian
infra-red
infrasonic
infrastructure
infrequency