The word "unsagacious" refers to a lack of wisdom or good judgment. Its antonyms would therefore include words that describe the opposite qualities, such as "intelligent," "wise," "clever," "astute," "sharp," "shrewd," "perceptive," and "sensible." Other possible antonyms might include "discerning," "knowledgeable," "insightful," "perspicacious," and "astute." These terms all suggest an ability to make good decisions and understand complex situations, which stands in stark contrast to the negative connotations of "unsagacious." By learning the antonyms for this word, we can better appreciate the nuances of language and use it more effectively to communicate our thoughts and ideas.