punishing

Adj.	1.	punishing - resulting in punishment; "the king imposed a punishing tax"
	2.	punishing - 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" Synonyms: arduous, backbreaking, grueling, gruelling, laborious, toilsome, hard, heavy

arduous, backbreaking, effortful, grueling, gruelling, hard, heavy, laborious, toilsome