The term 'do in' is a slang term meaning to KILL or destroy. The crossword solutions for this term are SLAY (4 letters), KILL (4 letters), ERASE (5 letters), BUTCHER (7 letters), SHATTER (7 letters), SLAUGHTER (9 letters), and INCAPACITATE (12 letters). All of these words can be used to describe the act of killing or destroying something, with varying degrees of intensity. SLAY and KILL are the most basic terms, while ERASE and SHATTER suggest more subtle destruction. BUTCHER, SLAUGHTER, and INCAPACITATE are more violent terms that imply a more intense level of destruction.