Noah Webster's New International Dictionary of the English Language

1. (a.) Marvelous; strange.

2. (a.) Having the qualities of a monster; deviating greatly from the natural form or character; abnormal; as, a monstrous birth.

3. (a.) Extraordinary in a way to excite wonder, dislike, apprehension, etc.; -- said of size, appearance, color, sound, etc.; as, a monstrous height; a monstrous ox; a monstrous story.

4. (a.) Extraordinary on account of ugliness, viciousness, or wickedness; hateful; horrible; dreadful.

5. (a.) Abounding in monsters.

6. (adv.) Exceedingly; very; very much.