Verb
(transitive, idiomatic, informal) To submit a suffering person or an animal to euthanasia.
(transitive, idiomatic, informal, figuratively) To end or destroy something for the good of the individuals involved in it.
(transitive, idiomatic, informal) To relieve somebody's anxiety by supplying information that they wanted to know.
Well, I'll put you out of your misery: the amount we won on the lottery was only ten dollars.