The crossword solutions for the term 'THAT'S OBVIOUS!' are 'DUH' (3 letters), 'IKNOW' (5 letters) and 'NODUH' (5 letters). These solutions are all slang terms used to express agreement or understanding of something that is obvious. The term 'DUH' is an expression of surprise, disbelief, or sarcasm in response to a statement that is obvious or self-evident. 'IKNOW' is a combination of the words 'I' and 'KNOW' and is used to express agreement with a statement that is obvious. Lastly, 'NODUH' is a combination of the words 'NO' and 'duh' and is used to express agreement with a statement that is obvious.