Oddly frightening (5)
I believe the answer is:
eerie
'oddly frightening' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for eerie that I've seen before include "Strangely frightening" , "Weird and disturbing" , "Awesome" , "Spine-tingling" , "Oddly frightening" .)