war·y (wâr??)adj. war·i·er, war·i·est 1. On guard; watchful: taught to be wary of strangers.2. Characterized by caution: a wary glance at the black clouds.[Middle English ware, from Old English wær; see wer- in Indo-European roots.]war?i·ly adv.war?i·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.