stal·wart (stôl?w?rt)adj.1. Loyal and resolute: a stalwart ally; stalwart support.2. Strong and imposing: a stalwart oak tree.n. One who steadfastly supports an organization or cause: party stalwarts.[Middle English, alteration of stalworth, from Old English st?lwierthe, serviceable, probably alteration of *statholwierthe, steadfast : stathol, foundation; see staddle + weorth, valuable; see wer- in Indo-European roots.]stal?wart·ly adv.stal?wart·ness n.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.