Extremely thin pointer found in home (9)
I believe the answer is:
narrowest
'extremely thin' is the definition.
I can't judge whether this definition defines the answer.
'pointer found in home' is the wordplay.
'pointer' becomes 'arrow' (synonyms).
'found in' is an insertion indicator.
'home' becomes 'nest' (a bird's home).
'arrow' placed into 'nest' is 'NARROWEST'.
Can you help me to learn more?
(Other definitions for narrowest that I've seen before include "Most confined" , "Most slender" , "Slightest" , "Extremely strict" , "this escape most lucky" .)