Noah Webster's New International Dictionary of the English Language

1. (superl.) Pleasing by delicacy or grace; attracting, but not striking or impressing; of a pleasing and attractive form a color; having slight or diminutive beauty; neat or elegant without elevation or grandeur; pleasingly, but not grandly, conceived or expressed; as, a pretty face; a pretty flower; a pretty poem.

2. (superl.) Moderately large; considerable; as, he had saved a pretty fortune.

3. (superl.) Affectedly nice; foppish; -- used in an ill sense.

4. (superl.) Mean; despicable; contemptible; -- used ironically; as, a pretty trick; a pretty fellow.

5. (superl.) Stout; strong and brave; intrepid; valiant.

6. (adv.) In some degree; moderately; considerably; rather; almost; -- less emphatic than very; as, I am pretty sure of the fact; pretty cold weather.