Meaning of monstrous

mon•strous

1. frightful or hideous, esp. in appearance; extremely ugly.
2. shocking or revolting; outrageous: monstrous cruelty.
3. extraordinarily great; huge; immense: a monstrous building.
4. deviating grotesquely from the natural or normal form or type.
5. having the nature or appearance of a fabulous monster.

1. extremely; exceedingly; very.