As adjectives the difference between rational and savvy
is that
rational is capable of reasoning while
savvy is (informal) shrewd, well-informed and perceptive.
As nouns the difference between rational and savvy
is that
rational is (mathematics) a rational number: a number that can be expressed as the quotient of two integers while
savvy is shrewdness.
As a verb savvy is
(informal) to understand.
As an interjection savvy is
(informal) do you understand?.