MOST SORDID is a term that describes something that is of the lowest moral character, or is considered to be extremely unpleasant. The crossword solutions BASEST (6 letters), SEAMIEST (8 letters), and MEANEST (7 letters) all describe something that is of the same low moral character as MOST SORDID. BASEST is the most basic form of sordidness, while SEAMIEST implies a slimy or slippery quality, and MEANEST suggests a cruel or malicious nature.