Wild dog almost biting relative is rather scary (8)
I believe the answer is:
daunting
'rather scary' is the definition.
'wild dog almost biting relative' is the wordplay.
'wild dog' becomes 'dingo' (dingo is a kind of wild dog).
'almost' means to remove the last letter (most of the word but not all of it).
'biting' means one lot of letters goes inside another (I've seen this in other clues).
'relative' becomes 'aunt' (aunt is a kind of relative).
'dingo' with its final letter taken away is 'ding'.
'ding' placed around 'aunt' is 'DAUNTING'.
'is' acts as a link.
(Other definitions for daunting that I've seen before include "Intimidating, discouraging" , "Scary" , "Making afraid or discouraged" , "tending to cow" .)