Position that’ll block official aid (6)
I believe the answer is:
relief
'aid' is the definition.
(I know that relief is a type of public assistance)
'position that'll block official' is the wordplay.
'position' becomes 'lie' (lie can mean to place or position).
'that'll block' is an insertion indicator (some letters block or plug a gap).
'official' becomes 'ref' (match official in football, say).
'lie' inserted into 'ref' is 'RELIEF'.
(Other definitions for relief that I've seen before include "Alleviation of pain or distress" , "Easement or assistance to people in need" , "Easement or assuagement" , "outstanding work" , "Ease given by removal of anxiety" .)