co-star vs star

co-star and star both are nouns.

Word	Noun	Adjective	Verb	Adverb
co-star	Yes	No	Yes	No
star	Yes	Yes	Yes	No

As nouns, star is a hypernym of co-star; that is, star is a word with a broader meaning than co-star:

co-star: one of two actors who are given equal status as stars in a play or film
star: an actor who plays a principal role

Other hypernyms of co-star include lead, principal.

As verbs, star is a hypernym of co-star; that is, star is a word with a broader meaning than co-star:

As verbs, star is a hypernym of co-star; that is, star is a word with a broader meaning than co-star:

co-star (noun)	star (noun)
one of two actors who are given equal status as stars in a play or film	the topology of a network whose components are connected to a hub
	a star-shaped character * used in printing
	(astronomy) a celestial body of hot gases that radiates energy derived from thermonuclear reactions in the interior
	any celestial body visible (as a point of light) from the Earth at night
	an actor who plays a principal role
	someone who is dazzlingly skilled in any field
	a performer who receives prominent billing
	a plane figure with 5 or more points; often used as an emblem

co-star (adjective)	star (adjective)
	indicating the most important performer or role

co-star (verb)	star (verb)
be the co-star in a performance	mark with an asterisk
feature as the co-star in a performance	be the star in a performance
	feature as the star