As an academic discipline in the Western world, philosophy is essentially the strategic and disciplined pursuit of wisdom, particularly wisdom about the most fundamental features of the world and human life.  We ask the really hard questions and we develop methods for pursuing answers.

What is it to know? Epistemology Ways of knowing, possible objects of knowledge, certainty and fallibility, consensus and dissent, etc.
What is good? Value Theory Morality, aesthetics, political and social justice, the value of lives and ways of living, etc.
What's real? Metaphysics Space, time, God, immortality of the soul, freedom of will, the nature of existence, the existence of nature, etc.
By what methods can I become wise? Logic Sentential and predicate logic, multivariate and fuzzy logics, non-deductive inference, fallacies and biases, etc.