varicose vein vs varicosity

varicose vein and varicosity both are nouns.

Word	Noun	Adjective	Verb	Adverb
varicose vein	Yes	No	No	No
varicosity	Yes	No	No	No

As nouns, varicosity is a hypernym of varicose vein; that is, varicosity is a word with a broader meaning than varicose vein:

varicose vein: a vein that is permanently dilated; most common in the legs
varicosity: varix or varicose condition in which a vein is swollen and tortuous

Other hypernyms of varicose vein include vein, vena, venous blood vessel.

varicose vein (noun)	varicosity (noun)
a vein that is permanently dilated; most common in the legs	varix or varicose condition in which a vein is swollen and tortuous