Why is the ninth month called September?
1570s, reprive, "take back to prison," alteration (perhaps by influence of reprove) of Middle English repryen "to remand, detain" (late 15c.), probably from Middle French repris, past participle of reprendre "take back" (see reprise). Meaning "to suspend an impending execution" is recorded from 1590s; this sense evolved because being sent back to prison was the alternative to being executed. Spelling with -ie- is from 1640s, perhaps by analogy of achieve, etc. Related: Reprieved; reprieving.
1590s, from reprieve (v.).