1
general::
1. Fail to succeed, be defeated, as in The election's over, and you've lost out. [Mid-1800s] 2. Also, lose out on or in. Miss an opportunity to participate, as in We came so late that we lost out on our chance to see her dance, or The Republicans lost out in last fall's elections. [Colloquial; mid-1900s] Also see MISS OUT ON.
American Heritage Idioms
2
general::
Phrase(s): lose out
1. to lose in competition; to lose one’s expected reward. • Our team lost out because our quarterback broke his leg. • I ran my best race, but I still lost out. 2. lose out (on something) Go to miss out (on something).
McGrawhill's American Idioms And Phrasal Verbs