Merriam-Webster's Collegiate® Dictionary, 11th Edition
MONSTROUS
I. adjective
Date: 15th century
strange , unnatural , having extraordinary often overwhelming size ; gigantic ,
3. having the qualities or appearance of a monster, teeming with monsters,
4. extraordinarily ugly or vicious ; horrible , shockingly wrong or ridiculous, deviating greatly from the natural form or character ; abnormal , very great, monstrously adverb monstrousness noun Synonyms: see: monstrous
II. adverb
Date: 1590
very , extremely