Burden in adjusting the wig (6)
I believe the answer is:
weight
'burden' is the definition.
(I know that burden can be written as weight)
'adjusting the wig' is the wordplay.
'adjusting' is an anagram indicator.
'the'+'wig'='thewig'
'thewig' with letters rearranged gives 'WEIGHT'.
'in' is the link.
(Other definitions for weight that I've seen before include "Gravitational pull" , "Vertical force as a result of gravity" , "Import" , "Pressure" , "Burden" .)