Antonyms for rare are common, unexceptional, frequent or (cooked) well done.
Worthless
Yes. Or usual and unusual; rare and common.
Rare
common, frequent
No, rare or uncommon is
RARE
in biology, the opposite is recessive in sexual behavior, the opposite is submissive in some terms, the opposite is rare
Rare
Words that are opposite of rude are:politecivilrespectfulnicemannerlypolishedconsiderateA rare use of the word rude is for accommodations, with the opposite refined.
no offence but i think that's pretty easy rare
rare
The opposite would be scarce, rare, uncommon, or sparse.