infelicity (n.)youdaoicibaDictYouDict[infelicity 词源字典]
late 14c., from Latin infelicitas "ill luck, misfortune," from infelix (genitive infelicis) "unfruitful, barren; unfortunate, unhappy, causing misfortune, unlucky," from in- "not, opposite of" (see in- (1)) + felix (see felicity).[infelicity etymology, infelicity origin, 英语词源]