Mean I will get, in the post (6)
I believe the answer is:
pillar
'the post' is the definition.
(a pillar is a post or column)
'mean i will get' is the wordplay.
'mean' becomes 'par' (average score on a golf course).
'i will' becomes 'I'll' (abbreviation).
'get' is an insertion indicator.
'par' enclosing 'ill' is 'PILLAR'.
'in' is the link.
(Other definitions for pillar that I've seen before include "monument?" , "Stylite would live on it" , "Tall support" , "person providing reliable support" , "Column; admired member (of community)" .)