Question

That he had been in excited and unusual moods was known to those who had been intimate with him, but nobody imagined that there had been shown in him _______ symptoms of the mental derangement, which bathsheba had momentarily suspected.

Answer 1

That he had been in excited and unusual moods was known to those who had been intimate with him, but nobody imagined that there had been shown in him unequivocal symptoms of the mental derangement, which bathsheba had momentarily suspected.

The word that fills the blank in the question is unequivocal.