Turnoff is a word that is used when you've suddenly loose interest in something. For instance, a woman goes on a date with somebody and this somebody get drunk too much. Than she can say something like "Sorry, but your behaviour was total turnoff".
Intuitively this is a very common concept but I'm failing to think of any good match in Ruassian. "Разочарование" is a different thing. What else? "Как отрезало" sounds like something actually more relevant but it's difficult to construct the whole phrase.