The term 'make harmless' can be defined by three crossword solutions: DEFUSE (6 letters), DISARM (6 letters), and unarm (5 letters). DEFUSE means to remove the fuse from an explosive device, making it safe. DISARM means to take away a weapon from someone, rendering them harmless. Unarm means to take away armor or protective clothing, leaving the person vulnerable. All three words refer to the idea of making something or someone harmless.