Refers to a personal or systematic set of beliefs about the meaning and conduct of life. Often used in philosophical or reflective contexts.
His philosophy of life is 'live each day as if it were your whole life.'
Compound of 生 (せい, 'life') + の (possessive particle) + 哲学 (てつがく, 'philosophy'). A straightforward calque or translation of the Western concept 'philosophy of life'.