Antonyms for "not parallel" include "parallel," "converging," "coincident," "aligned," "even," "level," and "straight." Parallel refers to things that run alongside each other without intersecting or touching, whereas converging is the opposite where two lines gradually come closer and closer together. Coincident implies that two things occur at the same time, place or coincide in meaning. Aligned means to be in a straight line or arrangement, and even suggests that something is consistent, level and equal. The antonym "not parallel" may also be expressed as "non-parallel," "divergent," or "oblique.