The omission of his name from the movie credits is regrettable.

He lied by omission when he failed to say that he had in fact been there that night.

It was an omission to not give the winner a prize.

Omission is a noun.

An omission is when something is left out.

Basically, omission is neglecting to do something and commission is doing something. The two words together are often associated with ethics and sin. Is it okay to just never do anything bad (omission) or must you also do good things (commission) to be a good member of society. Or in the religious context, is it okay to do good things (charitable acts) if you neglect to do those things that are expected of you (praying, going to church, etc.).

Lives of Omission was created in 2011.