par「完全に」、per-「完全に」から、-don「与える」、donate「寄付する」から、つまり完全に与えること、ひいてはpardon「罰を免除する」、主に「pardon me」という感嘆詞で使われる、許しを請うこと。
'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.