marked by qualities giving the power to produce an intended effect; "written propaganda is less efficacious than the habits and prejudices...of the readers"-Aldous Huxley; "the medicine is efficacious in stopping a cough"
having or showing or requiring special skill; "only the most skilled gymnasts make an Olympic team"; "a skilled surgeon has many years of training and experience"; "a skilled reconstruction of her damaged elbow"; "a skilled trade"