Of lines or planes, making with a given line, surface, or direction an angle that is less than 90°; neither perpendicular nor parallel; of angles, either acute or obtuse, not right; in general, not direct; aslant; slanting. See cuts under angle.Indirect, in a figurative sense: as, an oblique reproach or taunt.Questionable from a moral point of view; not upright or morally direct; evil.In botany, unequal-sided.n. In anatomy, an oblique muscle: as, the external oblique of the abdomen. See obliquus.To deviate from a direct line or from the perpendicular; slant; slope.To advance slantingly or obliquely; specifically (military), to advance obliquely by making a half-face to the right or left and marching in the new direction.n. In geometry, except the perpendicular, any sect from a point to a straight or a plane.