guiding motto for one's life; life principle
A personal maxim or precept that guides one's conduct and way of living. Often used in philosophical or self-help contexts.
His guiding motto for life is 'one good deed a day'.
I still cherish the life principle my grandmother taught me.
信条 refers to one's creed or beliefs, often in a broader ideological sense, whereas 処生訓 is more about practical daily conduct.
Compound of 処生 (life conduct) and 訓 (teaching, precept). The exact historical derivation is uncertain, but the kanji composition directly reflects the meaning.