1. To study or create theories about basic things such as the nature of existence or how people should live. English = do philosophy, study philosophy.
2. To talk or write about basic, important subjects such as life, often in a boring, pretentious way. English = philosophise.
3. To be concerned with or to relate to philosophy; or, more generally, to have a wise and accepting attitude to misfortune and suffering in life. English = (be) philosophical.