Noah Webster
Monstrous
MON'STROUS, adjective [Latin monstrosus.] Unnatural in form; out of the common course of nature; as a monstrous birth or production.
1. Strange; very wonderful; generally expressive of dislike.
2. Enormous; huge; extraordinary; as a monstrous highth; a monstrous tree or mountain.
3. Shocking to the sight or other senses; hateful.
MON'STROUS, adverb Exceedingly; very much; as monstrous hard; monstrous thick.
And will be monstrous witty on the poor.
[This use is colloquial and vulgar.]