trial-and-error

from WordNet (r) 3.0 (2006)

trial-and-error
    adj 1: trying out various means or theories until error is
           satisfactorily reduced or eliminated; "he argued that all
           learning is a trial-and-error process that resembles
           biological evolution"
    2: relating to solving problems by experience rather than
       theory; "they adopted a trial-and-error procedure"