The act of omitting; neglect or failure to do something required by propriety or duty.

That which is omitted or is left undone.

An omission is the failure to do one's individual and public duty by completing a particular act.

a mistake resulting from neglect

something that has been omitted; "she searched the table for omissions"

neglecting to do something; leaving out or passing over something

Neglecting to perform an act required by law or by professional duty.

Neglect to perform what the law requires.

a) Something neglected, left out, or left undone b) The act, fact, or state of leaving something out or failing to do something esp. that is required by duty. www.dictionary.com Keyword(s): Omission

In the criminal law, an omission or failure to act will constitute an actus reus (Latin for "guilty act") and give rise to liability only when the law imposes a duty to act and the defendant is in breach of that duty.

Omission is, in Catholic teaching, the failure to do something one can and ought to do. If this happens advertently and freely a sin is committed. The degree of guilt incurred by an omission is measured like that attaching to sins of commission, by the dignity of the virtue and the magnitude of the precept to which the omission is opposed as well as the amount of deliberation.