reprieve

First recorded in 1300–50; perhaps conflation of Middle English repreven “to contradict,” variant of reproven “to rebuke,” apparently taken in literal sense “to prove again, test again,” and Middle English repried (past participle of reprien “to bring back”), from Old French reprit (past participle of reprendre “to take back”; see reprise,reprove,

3. See pardon.

The history of reprieve is complicated and confusing. The past participle repryed “returned to prison,” dating to 1513, comes from Anglo-French and Old French repris, the past participle of reprendre, from Latin reprehendere (also reprendere ) “to hold fast, hold back, blame, find fault with, investigate (a crime), pass judgment on, convict.” The usual modern sense “to delay the impending punishment or sentence of a convict” comes from the notion that being returned to prison is preferable to being executed.
The current spelling reprieve, recorded more than a century later than the original spelling repry, is possibly due to the influence of the Middle English verb repreve(n) “to rebuke, condemn.”
The noun, first appearing in the late 16th century, is a simple functional shift (a change in grammatical function).