unsparing and uncompromising in discipline or judgment; "a parent severe to the pitch of hostility"- H.G.Wells; "a hefty six-footer with a rather severe mien"; "a strict disciplinarian"; "a Spartan upbringing"
practicing great self-denial; "Be systematically ascetic...do...something for no other reason than that you would rather not do it"- William James; "a desert nomad's austere life"; "a spartan diet"; "a spartan existence"