What is the synonym for monstrous?

Monstrous:adjective:
a. frighteningly hideous; frightfully ugly.
b. shocking, horrible, or atrocious.
c. extraordinarily or abnormally large; oversize; huge.

Synonyms for a & b:
atrocious, awful, beastly, dreadful, frightful, grotesque, gruesome, heinous, hideous, horrendous, horrible, horrific, loathsome, outrageous, repulsive, revolting, scary, terrible, terrifying, ugly, vile.

Synonyms for c:
beastly, big, enormous, gargantuan, giant, gigantic, huge, humongous, jumbo, large, oversize