Gruelling is a synonym of brutal.
As adjectives the difference between gruelling and brutal
is that gruelling
is so difficult or taxing as to make one exhausted; backbreaking while brutal
)savagely violent, vicious, ruthless, or cruel.
So difficult or taxing as to make one exhausted; backbreaking.
* (so difficult or taxing as to make one exhausted) backbreaking, exhausting
(senseid)Savagely violent, vicious, ruthless, or cruel
Crude or unfeeling in manner or speech.
Disagreeably precise or penetrating
(music, figuratively) In extreme metal, to describe the speed of the music and the density of riffs.