ax·i·o·mat·ic 
(ăk′sē-ə-mătĭk) also ax·i·o·mat·i·cal (-ĭ-kəl)
(ăk′sē-ə-mătĭk) also ax·i·o·mat·i·cal (-ĭ-kəl)adj.
Of, relating to, or resembling an axiom; self-evident: "It's axiomatic in politics that voters won't throw out a presidential incumbent unless they think his challenger will clean house" (Peter Grier).
ax′i·o·mati·cal·ly adv.