(1):

(a.) Alt. of Empirical

(2):

(n.) One who confines himself to applying the results of mere experience or his own observation; especially, in medicine, one who deviates from the rules of science and regular practice; an ignorant and unlicensed pretender; a quack; a charlatan.

(3):

(n.) One who follows an empirical method; one who relies upon practical experience.