Consider the following situation.
A prosecutor in court is asking questions of an expert witness. The responses are all negative with the expert always adding another explanation to the prosecutor's conclusions/diagnoses. The expert witness's attitude could be interpreted as obstructive but logical. The questioning continues and the responses are appropriate for the question but continue being negative.
The prosecutor feels that the witness is being [adjective I'm looking for] in their responses.
I know the word exists, but I've forgotten it.