The term 'deaf as a SIGN' is a phrase used to describe someone who is completely deaf and unable to hear. The crossword solutions for this term are SIGN (4 letters), SIGNS (5 letters), SMETANA (7 letters), APOS (4 letters), and APOST (5 letters). SIGN is a verb meaning to use hand gestures or symbols to communicate, while SIGNS are the hand gestures or symbols used in SIGN language. SMETANA is a Czech composer known for his operas and symphonic works. APOS and APOST are abbreviations for the word apostrophe, which is a punctuation mark used to indicate possession or omitted letters.