in for a penny, in for a pound

idiom

Definition of in for a penny, in for a pound

British

—used to say that a person should finish what he or she has started to do even though it may be difficult or expensive

"If you want to quit, I'll understand." "No, I'm sure we can do this. In for a penny, in for a pound."

penny play

: a monetary unit of the United Kingdom formerly equal to ¹/₂₄₀ pound but now equal to ¹/₁₀₀ pound
: a similar monetary unit of any of various other countries in or formerly in the Commonwealth of Nations — see pound at Money Table
: a coin representing one penny

pound play

: any of various units of mass and weight
: the basic monetary unit of the United Kingdom —called also pound sterling
: any of numerous basic monetary units of other countries (such as Egypt, Lebanon, Syria) — see Money Table