The term 'I DUNNO' is a slang expression used to indicate that one does not know the answer to a question. The crossword solutions for this term are HMM (3 letters), GOTME (5 letters), BEATSME (7 letters), and SEARCHME (8 letters). These solutions all express the idea of not knowing the answer to a question, with HMM being the shortest and most concise expression, and SEARCHME being the longest and most descriptive.