cornflakes + Add to list UK //kˈɔːnfleɪks// corn·flakes Idioms4 entries01pee in someone's cornflakesAlternative form of piss in someone's cornflakes.02pee on someone's cornflakesAlternative form of piss in someone's cornflakes.03piss in someone's cornflakesTo disappoint or irritate someone.Show 1 more