from The American Heritage® Dictionary of the English Language, 4th Edition
- adv. To a double degree; twice: doubly protected; made doubly certain.
- adv. In a twofold manner.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adv. In a double manner; twice the severity or degree.
- adv. in two ways
- adv. with duplicity
from the GNU version of the Collaborative International Dictionary of English
- adv. In twice the quantity; to twice the degree
- adv. Deceitfully.
from The Century Dictionary and Cyclopedia
- In a double or twofold manner; in twice the quantity or to twice the degree: as, to be doubly sensible of an obligation.
- Deceitfully; with duplicity.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adv. to double the degree
- adv. in a twofold manner
First known usage in the 15th century. (Wiktionary)