frightening vs terrorist act

frightening and terrorist act both are nouns.

Word	Noun	Adjective	Verb	Adverb
frightening	Yes	Yes	No	No
terrorist act	Yes	No	No	No

frightening (noun)	terrorist act (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)	terrorist act (adjective)
causing fear or dread or terror