sell-out (sell-outs plural ), sellout
1 n-count If a play, sports event, or other entertainment is a sell-out, all the tickets for it are sold.
Their concert there was a sell-out.
2 n-count If you describe someone's behaviour as a sell-out, you disapprove of the fact that they have done something which used to be against their principles, or given in to an opposing group., (disapproval)
For some, his decision to become a Socialist candidate at Sunday's election was simply a sell-out.