on a promise

on a promise

On the understanding that something will be done as someone has promised. He agreed to overtake the project on top of his existing work on a promise of a pay raise. We decided to let it go without punishing John on a promise that he will not attend any of these parties ever again.
See also: on, promise
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

on a promise

(of a person) confidently assured of something, especially of having sexual intercourse with someone. informal
See also: on, promise
Farlex Partner Idioms Dictionary © Farlex 2017
See also: