Put a damper on is an idiom that means to INHIBIT or DETER something. In other words, it is to put a stop to something or to reduce its intensity. The two crossword solutions for this term are INHIBIT (7 letters) and DETER (5 letters). INHIBIT means to restrain or hold back, while DETER means to discourage or prevent someone from doing something. Therefore, Put a damper on is an expression that suggests to restrain or discourage something.