Green’s Dictionary of Slang

lose out (on) v.

[note Asbury Sucker’s Progress (1938) 16: An extraordinary number of the terms, technical and otherwise, which were employed by Faro players in the palmy days of the game have passed into the language [...] Here are some of them: [...] Losing out—Betting on a card which loses four times in one deal]

1. to fail, to miss an opportunity.

[UK]H. Bushnell Sermons for New Life ix. 176: The child brought up a thief gets an infinite power of cunning and loses out just as much in the power of true perception [OED].
[US]H. Bushnell New Life viii 110: The child brought up a thief gets an infinite power of cunning [...] and loses out just as much in the power of true perception [DA].
[US]B. Fisher A. Mutt in Blackbeard Compilation (1977) 59: You’re supposed to take my picture flirting with this Parisian beauty and show it to the heiress which puts me on the bum and I lose out.
[US]J. London Valley of the Moon (1914) 174: We’re the white folks that lost out. We’re the ones that’s ben skinned.
[US]M.C. Sharpe Chicago May (1929) 126: We appealed to the Court of Cassation, the highest court of appeal, sitting at Versailles, and lost out.
[US]Blue Valley Farmer 3 Dec. 4/1: Down in the south and southwest, I am ‘losing out’ [DA].
[US]E. De Roo Go, Man, Go! 48: I don’t wanna lose out with her.
[UK]Indep. Rev. 5 Jan. 4: Despite the presence of Gazza and the world-famous Binns department store, they lose out as well.

2. (also lose out to) to be fooled, to be swindled.

[US]M.C. Sharpe Chicago May (1929) 120: Eddie had lost out in a job at Lyons, was sentenced to ten years, and served his time. He wanted to get his revenge on the frog-eaters.
[Aus]Baker Popular Dict. Aus. Sl. 44: LOSE OUT TO: To be swindled or deceived by someone.
[US]A. Hoffman Property Of (1978) 35: So I lost out with McKay. So?
[UK]Observer Rev. 27 June 3: And Britain? Have we lost out?