What is Sell out ?
Sell out is (verb) 1. to sell your business He sold out to his partner and re- tired to the seaside. 2. to sell all the stock of an item This item has sold out. Have you got it in a size 12? – No, I’m afraid we’re sold out. 3. to give in to a group of influential people The environmental group has ac- cused the government of selling out to the oil companies. sell out of
source: Easier English, Student Dictionary Upper Intermediate Level