The term INANE ONE can be broken down into four crossword solutions: TWIT (4 letters), ASS (3 letters), DOPE (4 letters), and GOOSE (5 letters). TWIT is a slang term for a foolish or silly person, while ASS is a slang term for a fool or an idiot. DOPE is a slang term for someone who is stupid or foolish, and GOOSE is a slang term for a silly or foolish person. All of these terms are used to describe someone who is inane or lacking in intelligence.