Function: transitive verb
Date: 1678
1 : to add as a gratuity or supplement
2 : to introduce or interject in the course of something : CONTRIBUTE <they throw in some ⋯ sound effects on several songs ― Tom Phillips>
3 : DISTRIBUTE 3B
4 : ENGAGE < throw in the clutch>
intransitive verb : to enter into association or partnership : JOIN <agrees to throw in with a crooked ex-cop ― Newsweek >
– throw in the towel also throw in the sponge : to abandon a struggle or contest : acknowledge defeat : GIVE UP