na-adjective, noun
Rare literary term for steadfast loyalty or faithfulness, often with a nuance of mature, seasoned devotion. Not used in everyday speech.
彼の老実な性格は、長年の信頼を築いた。
His loyal character built trust over many years.
老実の士として、最後まで主君に仕えた。
As a man of fidelity, he served his lord to the end.