A somewhat formal or literary noun combining loyalty and affection, often used in contexts of feudal loyalty or deep personal devotion.
彼は主君に忠愛を尽くした。
He devoted his loyalty and affection to his lord.
忠愛
Serve the country with a heart of loyalty and devotion.
Compound of 忠 (loyalty) and 愛 (love, affection). The exact historical derivation is uncertain, but the combination is used to express a deep, affectionate loyalty.