Underestimate is a word that describes the act of undervaluing or dismissing something or someone's abilities or potential. Synonyms for underestimate include "underrate," which suggests a similar undervaluing of something's worth, "underappreciate," which implies a lack of gratitude or recognition for someone's efforts, and "understate," which connotes a lack of emphasis or exaggeration of something's significance. Other synonyms for underestimate include "disparage," "discount," "belittle," and "neglect." These words all describe the act of not fully recognizing the true value of something or someone, and they can help us to better understand the nuances of our language and our interactions with others.