antiterror

Etymology tree
Proto-Indo-European *h₂ent-
Proto-Indo-European *-s
Proto-Indo-European *h₂énts
Proto-Indo-European *-i
Proto-Indo-European *h₂énti
Ancient Greek ᾰ̓ντῐ́ (ăntĭ́)
Ancient Greek ἀντι- (anti-)der.
English anti-
Proto-Indo-European *tres-
Proto-Indo-European *-yeti
Proto-Indo-European *-éyeti
Proto-Indo-European *troséyeti
Proto-Italic *trozeō
Latin terreō
Proto-Indo-European *-os
Proto-Indo-European *-s
Proto-Indo-European *-ōs
Proto-Italic *-ōs
Latin -or
Latin terrorbor.
Old French terreur
Middle French terreurbor.
Middle English terrour
English terror
English antiterror
From anti- + terror.