Definitions for "Heinous"
Hateful; hatefully bad; flagrant; odious; atrocious; giving great offense; -- applied to deeds or to character.
shockingly brutal or cruel; "murder is an atrocious crime"; "a grievous offense against morality"; "a grievous crime"; "no excess was too monstrous for them to commit"
Awful, scary, monstrous; any activity fraught with extreme danger.
Keywords:  horrible
Really really horrible.
An adjective, which when used, increases the relative difficulty of the climb you are describing by at least two grades.