If you describe something as unsettling, you mean that it makes you feel rather worried or uncertain. The prospect of change of this kind has an unsettling effect on any organisation = disturbing + unsettlingly un·set·tling·ly It was unsettlingly quiet. making you feel nervous or worried
If something unsettles you, it makes you feel rather worried or uncertain. The presence of the two policemen unsettled her. = disturb. to make someone feel slightly nervous, worried, or upset