(1):

(n.) One versed or experienced in the science of government; one devoted to politics; a statesman.

(2):

(n.) One primarily devoted to his own advancement in public office, or to the success of a political party; - used in a depreciatory sense; one addicted or attached to politics as managed by parties (see Politics, 2); a schemer; an intriguer; as, a mere politician.

(3):

(a.) Cunning; using artifice; politic; artful.