1620s, "to pray against or for deliverance from, pray the removal or deliverance from," from Latin deprecatus, past participle of deprecari "to pray (something) away," from de "away" (see de-) + precari "to pray" (from PIE root *prek- "to ask, entreat"). Meaning "to express disapproval, urge against" is from 1640s. Related: Deprecated, deprecating.
