twitching vs blepharism

twitching and blepharism both are nouns.

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

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

twitching: a sudden muscle spasm; especially one caused by a nervous condition
blepharism: condition in which a person blinks continuously

Other hyponyms of twitching include tic, fibrillation, fasciculation.

twitching (noun)	blepharism (noun)
a sudden muscle spasm; especially one caused by a nervous condition	condition in which a person blinks continuously