Twig seen as son loosened grip (5)
I believe the answer is:
sprig
'twig' is the definition.
(I know that twig can be written as sprig)
'son loosened grip' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'loosened' is an anagram indicator.
'grip' anagrammed gives 'prig'.
's'+'prig'='SPRIG'
'seen as' is the link.
(Other definitions for sprig that I've seen before include "A tack; a little shoot" , "Small stem taken from a bush or plant" , "Younger member of family" , "Small stem bearing flowers" , "related to Spike and Brad" .)