Lashon Hara
Question
Is it lashon hara to say something ambiguous? Ie someone was,saying she did not consider that someone behaved correctly. I said "no" meaning I did not agree but later realised this,could be construed as agreement ie "no she did not behave correctly "
Answer
Shalom!
Thank you for your question.
Generally, It is not possible to issue a ruling on the permissibility of a specific phrase or word. There are so many other factors to consider, such as: the context, who will hear, what the inference of the statement will be, who is the person being spoken of, the tone of voice, and much much more.
in your case however it seems that since this is the normal way of speaking by saying "no" means you disagree, than it would not be considered Lashon Hara.
The main thing is to try our best!