anxiousness vs panic

anxiousness and panic both are nouns.

Word	Noun	Adjective	Verb	Adverb
anxiousness	Yes	No	No	No
panic	Yes	No	Yes	No

As nouns, panic is a hyponym of anxiousness; that is, panic is a word with a more specific, narrower meaning than anxiousness:

anxiousness: (psychiatry) a relatively permanent state of worry and nervousness occurring in a variety of mental disorders, usually accompanied by compulsive behavior or attacks of panic
panic: sudden mass fear and anxiety over anticipated events

Other hyponyms of anxiousness include castration anxiety, hypochondria, hypochondriasis, overanxiety, scare, social anxiety.

anxiousness (noun)	panic (noun)
a feeling of mild anxiety about possible developments	an overwhelming feeling of fear and anxiety
(psychiatry) a relatively permanent state of worry and nervousness occurring in a variety of mental disorders, usually accompanied by compulsive behavior or attacks of panic	sudden mass fear and anxiety over anticipated events

anxiousness (verb)	panic (verb)
	be overcome by a sudden fear
	cause sudden fear in or fill with sudden panic