frightening vs act of terrorism

frightening and act of terrorism both are nouns.

Word	Noun	Adjective	Verb	Adverb
frightening	Yes	Yes	No	No
act of terrorism	Yes	No	No	No

frightening (noun)	act of terrorism (noun)
the act of inspiring with fear	the calculated use of violence (or the threat of violence) against civilians in order to attain goals that are political or religious or ideological in nature; this is done through intimidation or coercion or instilling fear

frightening (adjective)	act of terrorism (adjective)
causing fear or dread or terror