The term 'make illegal' can be defined by five different crossword solutions: PROHIBIT (8 letters), OUTLAW (6 letters), ABOLISH (7 letters), BAN (3 letters), and Criminaze (9 letters). PROHIBIT means to forbid or prevent something from happening, while OUTLAW means to declare something illegal. ABOLISH means to do away with something completely, and BAN means to forbid or PROHIBIT something. Finally, Criminaze means to make something a criminal offense. All of these words refer to the act of making something illegal.