1.  straightness(n = noun.attribute) - (of hair) lack of a tendency to curl;
is a kind of curvature, curve
Antonym: curliness
Derived form adjective straight₃

2.  straightness(n = noun.attribute) - freedom from crooks or curves or bends or angles;
is a kind of configuration, conformation, contour, form, shape
Antonym: crookedness
Derived forms adjective straight₂, adjective straight₈

3.  straightness(n = noun.attribute) directness - trueness of course toward a goal; "rivaling a hawk in directness of aim"
is a kind of characteristic
has particulars: downrightness, straightforwardness, immediacy, immediateness, pointedness
Derived form adjective straight₁₄

4.  straightness(n = noun.attribute) good faith - having honest intentions; "he acted in good faith"; "doubt was expressed as to the good faith of the immigrants"
is a kind of honestness, honesty
Derived forms adjective straight₁₂, adjective straight₆

5.  straightness(n = noun.act) heterosexualism, heterosexuality - a sexual attraction to (or sexual relations with) persons of the opposite sex;
is a kind of sex, sex activity, sexual activity, sexual practice
Derived form adjective straight₁₀

   The quality, condition, or state, of being straight; as, the straightness of a path. [1913 Webster]

   A variant of Straitness. [1913 Webster]

N  straightness, rectilinearity, directness, inflexibility, straight line, right line, direct line, short cut, straight, rectilinear, rectilineal, direct, even, right, true, in a line, unbent, virgate, undeviating, unturned, undistorted, unswerving, straight as an arrow, inflexible, laser-straight, ramrod-straight.