The definition of arduous is a way of describing something that is extremely tiring and difficult.
Demanding great exertion; arduous and exhausting.
Using or based on data that are readily quantified or verified:
Hard to lift or move because of great weight; weighty
Marked by or requiring long, hard work:
Very busy; industrious
Characterized by or requiring toil.
Find another word for gruelling. In this page you can discover 12 synonyms, antonyms, idiomatic expressions, and related words for gruelling, like: arduous, backbreaking, grueling, hard, heavy, laborious, operose, punishing, toilsome, and null.