If you describe something as unnerving, you mean that it makes you feel worried or uncomfortable. It is very unnerving to find out that someone you see every day is carrying a potentially deadly virus. = disconcerting
inspiring fear; "the formidable prospect of major surgery"; "a tougher and more redoubtable adversary than the heel-clicking, jackbooted fanatic"- G H Johnston; "something unnerving and prisonlike about high gray wall"