| Noun | 1. | straightness - of hair: lack of a tendency to curlcurvature, curve - the property possessed by the curving of a line or surface | |
| 2. | straightness - freedom from crooks or curves or bends or anglescrookedness - having or distinguished by crooks or curves or bends or angles | |
| 3. | straightness - trueness of course toward a goal; "rivaling a hawk in directness of aim" | |
| 4. | straightness - having honest intentions; "he acted in good faith"; "doubt was expressed as to the good faith of the immigrants" | |
| 5. | straightness - a sexual attraction to (or sexual relations with) persons of the opposite sex | |