Flounder perhaps to acquire home that's complete (6)
I believe the answer is:
finish
'complete' is the definition.
(I know that complete can be written as finish)
'flounder perhaps to acquire home' is the wordplay.
'flounder perhaps' becomes 'fish' (flounder is a kind of fish).
'to acquire' means one lot of letters goes inside another.
'home' becomes 'in' ('he's home' can mean 'he's in').
'fish' enclosing 'in' is 'FINISH'.
'that's' acts as a link.
(Other definitions for finish that I've seen before include "Bring to an close" , "Refinement in social graces" , "Deal with" , "Pefect" , "Treatment of surface" .)