Vague family member stripped bark (7)
I believe the answer is:
unclear
'vague' is the definition.
(similar in meaning)
'family member stripped bark' is the wordplay.
'family member' becomes 'uncle' (brother of a parent).
'stripped' says to take the centre (outside letters removed).
The middle letters of 'bark' are 'ar'.
'uncle'+'ar'='UNCLEAR'
(Other definitions for unclear that I've seen before include "Poorly described" , "Nebulous" , "hard to understand" , "Not transparent or free from doubt" , "in clouds?" .)