The term 'Blue Material' can refer to a variety of different things. The four crossword solutions for this term are PORN (4 letters), SMUT (4 letters), EROTICA (7 letters), and PORNO (5 letters). PORN and PORNO are both slang terms for explicit sexual material, while SMUT is a more general term for obscene or indecent material. EROTICA is a more literary term for sexually explicit material that is intended to be arousing. DENIM (5 letters) is a type of sturdy cotton fabric, usually blue in color, that is commonly used to make clothing.