A nut case is a slang term for someone who is mentally unstable or unbalanced. The crossword solutions for the term nut case include SHELL (5 letters), CRANK (5 letters), KOOK (4 letters), LOON (4 letters), PSYCHO (6 letters), CRACKPOT (8 letters), LUNATIC (7 letters), BUR (3 letters), qzw (3 letters), and toolkit (7 letters). These words all have similar meanings to nut case, and can be used to describe someone who is mentally unwell.