These examples are from the Cambridge English Corpus and from sources on the web. Fool me once, shame on you. 2. a. Discover the definition of 'Fool me once, shame on you; fool me twice, shame on me' in our extensive dictionary of English idioms and idiomatic expressions. If you fool me again, then it's my fault because I was stupid enough to be fooled twice, so I … -- This means that the first time you fool me then it's your fault and you should feel ashamed. There is a common expression: "Fool me once, shame on you. Fool me once, shame on you; fool me twice, shame on me phrase. Definitions by the largest Idiom Dictionary. Fool me once, shame on you; fool me twice, shame on me - Idioms by The Free Dictionary. shame (shām) n. 1. a. What does Fool me once, shame on you; fool me twice, shame on me expression mean? b. Shame on you! You know better than to steal your sister's toys! Shame on Me Lyrics: Ok, number seven! / Shame on me for loving you / Can't deny that you've been untrue / You lie so sweet but you love to tease / Putting out fire with your gasoline / Woah! Shame on her for taking advantage of your feelings like that! Yeah! A painful emotion caused by the belief that one is, or is perceived by others to be, inferior or unworthy of affection or respect because of one's actions, thoughts, circumstances, or experiences: felt shame for having dropped out of school. See also: on, shame shame on you a phrase scolding someone for being naughty. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. Fool me twice, shame on me." Respect for propriety or morality: Have you no shame? Fool me twice, shame on me. What does the idiom 'Fool me once, shame on you; fool me twice, shame on me' mean? Does anybody know waht's the equivalent in Spanish for, "shame on me" e.g. "I forgot to call yesterday, shame on me for not doing it". shame on (one) An expression of condemnation, often an angry or disappointed one.