not easily borne; wearing; "the burdensome task of preparing the income tax return"; "my duties weren't onerous; I only had to greet the guests"; "a taxing schedule"
difficult to accomplish; demanding considerable mental effort and skill; "the arduous work of preparing a dictionary"
characterized by toilsome effort to the point of exhaustion; especially physical effort; "worked their arduous way up the mining valley"; "a grueling campaign"; "hard labor"; "heavy work"; "heavy going"; "spent many laborious hours on the project"; "set a punishing pace"
taxing to the utmost; testing powers of endurance; "his final, straining burst of speed"; "a strenuous task"; "your willingness after these six arduous days to remain here"- F.D.Roosevelt
without delay or hesitation; with no time intervening; "he answered immediately"; "found an answer straightaway"; "an official accused of dishonesty should be suspended forthwith"; "Come here now!"
near or close by; "he passed immediately behind her"
bearing an immediate relation; "this immediately concerns your future"
not subject to the control of the will; "involuntary manslaughter"; "involuntary servitude"; "an involuntary shudder"; "It (becoming a hero) was involuntary. They sank my boat"- John F.Kennedy
controlled by the autonomic nervous system; without conscious control; "involuntary muscles"; "gave an involuntary start"