monstrous

Shockingly hideous or frightful in appearance.

Of or resembling a fabulous monster.

Exceptionally large; enormous.

Extremely immoral or cruel.

Deviating greatly from the norm in appearance or structure; abnormal.

Exceedingly; extremely; wonderfully: as, monstrous difficult.

Of unnatural formation; deviating greatly from the natural form or structure; out of the common course of nature: as, a monstrous birth or production.

Enormous; huge; prodigious; unparalleled.

Shocking; hateful; horrible: as, a monstrous delusion.