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
free from duties or responsibilities; "he writes in his leisure hours"; "life as it ought to be for the leisure classes"- J.J.Chapman; "even the artist and the sculptor were not regarded...as leisured men"- Ida Craven
obtainable or accessible and ready for use or service; "kept a fire extinguisher available"; "much information is available through computers"; "available in many colors"; "the list of available candidates is unusually long"
convenient for use or disposal; "the house is available after July 1"; "2000 square feet of usable office space"
not busy; not otherwise committed; "he was not available for comment"; "he was available and willing to accompany her"
intelligence activities concerned with identifying and counteracting the threat to security posed by hostile intelligence organizations or by individuals engaged in espionage or sabotage or subversion or terrorism