Webster's Revised Unabridged Dictionary · 1913

Monster

Monster (mon*stẽr) , noun

[Old English monstre, French monstre, from Latin monstrum, orig., a divine omen, indicating misfortune; akin of monstrare to show, point out, indicate, and monere to warn. See Monition, and compare Demonstrate, Muster.]

1.
Something of unnatural size, shape, or quality; a prodigy; an enormity; a marvel.
A monster or marvel. — Chaucer
2.
Specifically, an animal or plant departing greatly from the usual type, as by having too many limbs.
3.
Any thing or person of unnatural or excessive ugliness, deformity, wickedness, or cruelty.

Monster , adjective

1.
Monstrous in size. — Pope
2.
Enormous or very powerful; as, he drove a monster Harley. [informal]

Monster , transitive verb

To make monstrous. [Obsolete] — Shakespeare