The term 'Feeling BLAH' is often used to describe a feeling of being unwell, tired, or generally unenthusiastic. The crossword solutions for this term are 'ILL' (3 letters) and 'MOPISH' (6 letters). 'ILL' is an adjective meaning not in good health or suffering from an illness. 'MOPISH' is an adjective meaning listless, dull, or lacking enthusiasm. Together, these two words provide a comprehensive description of the feeling of being 'BLAH'.