pardon (v.) Look up pardon at Dictionary.com
mid-15c., "to forgive for offense or sin," from Old French pardoner (see pardon (n.)).
'I grant you pardon,' said Louis XV to Charolais, who, to divert himself, had just killed a man; 'but I also pardon whoever will kill you.' [Marquis de Sade, "Philosophy in the Bedroom"]
Related: Pardoned; pardoning. Pardon my French as exclamation of apology for obscene language is from 1895.
pardon (n.) Look up pardon at Dictionary.com
late 13c., "papal indulgence," from Old French pardon, from pardoner "to grant; forgive" (11c., Modern French pardonner), "to grant, forgive," from Vulgar Latin *perdonare "to give wholeheartedly, to remit," from Latin per "through, thoroughly" (from PIE root *per- (1) "forward," hence "through") + donare "give as a gift," from donum "gift," from PIE *donum "gift," from root *do- "to give."

Meaning "passing over an offense without punishment" is from c. 1300, also in the strictly ecclesiastical sense; sense of "pardon for a civil or criminal offense; release from penalty or obligation" is from late 14c. earlier in Anglo-French. Weaker sense of "excuse for a minor fault" is attested from 1540s.