To send; to dispatch.

“Have you sent off your application yet?”

To emit; to emanate.

To show someone a red card, and dismiss them from the playing area.

A penalty for a serious infraction of the rules in which the player is ordered to leave for the rest of the game; red card

A party for a person (i.e. a fellow employee) who is leaving; a farewell party.

“We had a sendoff for our departing colleague as he left for a new job.”

A party to recognize the passing (death) of a friend and allow survivors to reminisce about the person's life.