The term 'witless one' can be defined by four crossword solutions: DOLT (4 letters), SCHMO (5 letters), DODO (4 letters), and MORON (5 letters). DOLT is a slang term for a stupid or foolish person, while SCHMO is another slang term for a foolish or gullible person. DODO is an extinct bird that was known for its lack of intelligence, while MORON is a derogatory term for someone who is considered to be very unintelligent. All four terms can be used to describe someone who is witless.