- Not straightforward; indirect; obscure; hence, disingenuous; underhand; perverse; sinister.
- Not erect or perpendicular; neither parallel to, nor at right angles from, the base; slanting; inclined.
- (botany, of leaves) Having the base of the blade asymmetrical, with one side larger or extending further than the other.
- Not direct in descent; not following the line of father and son; collateral.
- (geometry) An oblique line.
- (grammar) The oblique case.
- The punctuation sign "/"
- (intransitive) To deviate from a perpendicular line; to move in an oblique direction.
- (transitive, computing) To slant (text, etc.) at an angle.
- (military) To march in a direction oblique to the line of the column or platoon; — formerly accomplished by oblique steps, now by direct steps, the men half-facing either to the right or left.