The term 'conversation stopper' refers to a phrase or sound that is used to abruptly end a conversation. The three crossword solutions for this term are DIN, GAG, and AHEM. DIN is an abbreviation of the word 'DIN, ' which is a loud, unpleasant noise. GAG is an abbreviation of the word 'GAG, ' which is a joke or remark that is intended to be humorous but is often seen as offensive or inappropriate. Finally, AHEM is an abbreviation of the word 'ahem, ' which is a sound made to attract attention or to express disapproval or embarrassment. All three of these words can be used to abruptly end a conversation.