straight line vs curve

straight line and curve both are nouns.

Word	Noun	Adjective	Verb	Adverb
straight line	Yes	No	No	No
curve	Yes	No	Yes	No

straight line (noun)	curve (noun)
a line traced by a point traveling in a constant direction; a line of zero curvature	a pitch of a baseball that is thrown with spin so that its path curves as it approaches the batter
	curved segment (of a road or river or railroad track etc.)
	the property possessed by the curving of a line or surface
	a line on a graph representing data
	the trace of a point whose direction of motion changes

straight line (verb)	curve (verb)
	form a curl, curve, or kink
	turn sharply; change direction abruptly
	form an arch or curve
	bend or cause to bend
	extend in curves and turns