upright in position or posture; "an erect stature"; "erect flower stalks"; "for a dog, an erect tail indicates aggression"; "a column still vertical amid the ruins"; "he sat bolt upright"
operating or moving or allowing movement in one direction only; "a unidirectional flow"; "a unidirectional antenna"; "a unidirectional approach to a problem"
earnest and conscientious activity intended to do or accomplish something; "made an effort to cover all the reading material"; "wished him luck in his endeavor"; "she gave it a good try"