a. Strong and healthy; robust: "Her splendid, vigorous body lay still and relaxed under the loose folds of her clothing" (Willa Cather).
b. Growing or spreading rapidly: a vigorous vine.
2. Characterized by or done with force and energy: "With a vigorous shake to get rid of the brine in his hair, he ran into the woods to hunt small game" (John Muir). See Synonyms at active.
3. Forceful; effective: a model of vigorous prose.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.