Intromission :: Intromission (n.) The act of sending in or of putting in; insertion.
Intromission :: Intromission (n.) An intermeddling with the affairs of another, either on legal grounds or without authority..
Omission :: Omission (n.) The act of omitting; neglect or failure to do something required by propriety or duty.
Omission :: Omission (n.) That which is omitted or is left undone.