CRAZY' (4 letters) The crossword solutions for the term 'LUNATIC, SLANGILY' are 'NUT' (3 letters) and 'CRAZY' (4 letters). Lunatic is a term used to describe someone who is mentally ill or unstable. Slangily refers to the use of informal language, which in this case is the word 'CRAZY'. Therefore, the two crossword solutions together can be interpreted as a slang term for someone who is mentally ill or unstable, which is 'NUT' or 'CRAZY'.