Spartan
adjective
unsparing and uncompromising in discipline or judgment; - H.G.Wells
“a parent severe to the pitch of hostility”
Similar: severe
adjective
of or relating to or characteristic of Sparta or its people
adjective
resolute in the face of pain or danger or adversity
“spartan courage”
adjective
practicing great self-denial; - William James
“Be systematically ascetic...do...something for no other reason than that you would rather not do it”
Similar: ascetic, ascetical, austere