Causing goosebumps (6)
I believe the answer is:
creepy
'causing goosebumps' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for creepy that I've seen before include "Causing feelings of fear or repulsion" , "Not wholesome" , "Rather eerie" , "Likely to cause goose pimples" , "Mysterious" .)