straightness vs curvature

straightness and curvature both are nouns.

Word	Noun	Adjective	Verb	Adverb
straightness	Yes	No	No	No
curvature	Yes	No	No	No

As nouns, curvature is a hypernym of straightness; that is, curvature is a word with a broader meaning than straightness:

Other hypernyms of straightness include curve.

straightness (noun)	curvature (noun)
a sexual attraction to (or sexual relations with) persons of the opposite sex	the rate of change (at a point) of the angle between a curve and a tangent to the curve
freedom from crooks or curves or bends or angles	the property possessed by the curving of a line or surface
(of hair) lack of a tendency to curl	(medicine) a curving or bending; often abnormal
having honest intentions
trueness of course toward a goal