the act of departing from the right, normal, or usual course.

the act of deviating from the ordinary, usual, or normal type.

deviation from truth or moral rectitude.

mental irregularity or disorder, esp. of a minor or temporary nature; lapse from a sound mental state.

Astronomy . apparent displacement of a heavenly body, owing to the motion of the earth in its orbit.

Optics . any disturbance of the rays of a pencil of light such that they can no longer be brought to a sharp focus or form a clear image.

Photography . a defect in a camera lens or lens system, due to flaws in design, material, or construction, that can distort the image.

noun

conformity , normality , regularity , soundness , sameness

noun

delusion , eccentricity , oddity , peculiarity , quirk , strangeness , weirdness , departure , deviation , difference , distortion , divergence , diversion , irregularity , lapse , straying , wandering , divergency , aberrance , aberrancy , anomaly , deviance , deviancy , preternaturalness , unnaturalness , brainsickness , craziness , dementia , derangement , disturbance , insaneness , lunacy , madness , mental illness , psychopathy , unbalance , abnormity , change , error , failure , hallucination , mania , phobia , warpage