tic vs twitching

tic and twitching both are nouns.

Word	Noun	Adjective	Verb	Adverb
tic	Yes	No	No	No
twitching	Yes	No	No	No

As nouns, twitching is a hypernym of tic; that is, twitching is a word with a broader meaning than tic:

tic: a local and habitual twitching especially in the face
twitching: a sudden muscle spasm; especially one caused by a nervous condition

Other hypernyms of tic include twitch, vellication.

tic (noun)	twitching (noun)
a local and habitual twitching especially in the face	a sudden muscle spasm; especially one caused by a nervous condition