#1 monstrous s. abnormally large. wn
#2 monstrous s. [atrocious, flagitious, grievous] 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". wn
#3 monstrous s. [grotesque] distorted and unnatural in shape or size; abnormal and hideous; "tales of grotesque serpents eight fathoms long that churned the seas"; "twisted into monstrous shapes". wn
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