The term 'EXTREMELY DARK' can be described by three crossword solutions: INKY (4 letters), EBON (4 letters), and PITCHBLACK (10 letters). INKY is an adjective used to describe something that is very dark, like the color of ink. EBON is an adjective used to describe something that is black or very dark in color. PITCHBLACK is an adjective used to describe something that is completely dark, like the color of pitch. All three words are used to describe something that is extremely dark.