sinecure: [17] Sinecure means literally ‘without cure’. It comes from the Latin phrase beneficium sine cūrā ‘benefice without cure’, that is to say an ecclesiastical office that does not involve the cure of souls (looking after people’s spiritual welfare), the usual duty of a priest. Hence it came to be applied to any appointment that involves payment for no work. [sinecure etymology, sinecure origin, 英语词源]
1660s, "church benefice with an emolument but without parish duties," from Medieval Latin beneficium sine cura "benefice without care" (of souls), from Latin sine "without" (see sans) + cura, ablative singular of cura "care" (see cure (n.1)).