Webster's Revised Unabridged Dictionary · 1913

Otherwise

Otherwise , adverb

[Other + wise manner.]

1.
In a different manner; in another way, or in other ways; differently; contrarily. — Chaucer
Thy father was a worthy prince, And merited, alas! a better fate; But Heaven thought otherwise. — Addison
2.
In other respects.
It is said, truly, that the best men otherwise are not always the best in regard of society. — Hooker
3.
In different circumstances; under other conditions; as, I am engaged, otherwise I would accept.
Let no man think me a fool; if otherwise, yet as a fool receive me. — 2 Cor. xi. 16
Her eyebrows... rather full than otherwise. — Fielding

Otherwise, like so and thus, may be used as a substitute for the opposite of a previous adjective, noun, etc.