DUNNO Meaning of DUNNO in English dun ‧ no /ˈdʌnəʊ $ -noʊ/ BrE AmE a way of saying ‘I don’t know’. Some people think that this use is not correct English:‘Do you want to come?’ ‘I dunno, I might.’ Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012