English
terroristical
From terrorist + -ical.
Formed from terrorist + -ical
Proto-Indo-European *tres- ‘to tremble (with fear)’
…
Old French terreur ‘terror’
Middle French terreur ‘terror’
Middle English terrour ‘a terror; a fright’
English terror
English terrorist
Today it means
adj Of or relating to terrorists
Language periods are conventional ranges, not dates for this word.
Etymograph / terroristical