I believe the sense of the noun 'a turn-off' derived from the verb 'to turn off' here means 'something that will put people off from the message of the document / will lose their interest, etc.' — it all depends on what this document is all about.

The term is used colloquially, often with a potential sexual connotation, in expressions like "He's a real turn-off!"

I believe the meaning as used here is similar to the verb 'to put off', which might in some situations be translated using 'dissuader'.

Of course, once arrived at the basic meaning, you'll now have to find a concise way of expressing this idea as a noun, as it is being used here!

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Note added at 2 heures (2015-11-29 07:13:30 GMT)
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I don't believe your suggestion of 'conclusion' would be applicable here — that sounds to me more like a translation of 'sign-off'.