c. 1300, philosophie, "knowledge, learning, scholarship, scholarly works, body of knowledge," from Old French filosofie "philosophy, knowledge" (12c., Modern French philosophie) and directly from Latin philosophia, from Greek philosophia "love of knowledge, pursuit of wisdom; systematic investigation," from philo- "loving" (see philo-) + sophia "knowledge, wisdom," from sophis "wise, learned;" a word of unknown origin [Beekes]. With many spelling variants in Middle English (filozofie, phelosophie, etc.).
From mid-14c. as "the discipline of dealing in rational speculation or contemplation;" from late 14c. as "natural science," also "alchemy, occult knowledge;" in the Middle Ages the word was understood to embrace all speculative sciences. Meaning "system a person forms for conduct of life" is attested from 1771. The modern sense of "the body of highest truth, the science of the most fundamental matters" is from 1794.
Nec quicquam aliud est philosophia, si interpretari velis, praeter studium sapientiae; sapientia autem est rerum divinarum et humanarum causarumque quibus eae res continentur scientia. [Cicero, "De Officiis"]
[Philosophical problems] are, of course, not empirical problems; but they are solved through an insight into the workings of our language, and that in such a way that these workings are recognized -- despite an urge to misunderstand them. The problems are solved, not through the contribution of new knowledge, rather through the arrangement of things long familiar. Philosophy is a struggle against the bewitchment (Verhexung) of our understanding by the resources of our language. [Ludwig Wittgenstein, "Philosophical Investigations," 1953]