By the sound of it, consideration nailed down (6)
I believe the answer is:
tacked
'nailed down' is the definition.
(tack can mean to fix or nail down)
'by the sound of it consideration' is the wordplay.
'by the sound of it' shows a homophone (sound like).
'consideration' becomes 'tact' (tact is a kind of consideration).
'tact' sounds like 'TACKED'.
(Other definitions for tacked that I've seen before include "Changed course" , "Turned into the wind, as sailors do" , "Zig-zagged (in a sailing boat); fixed" , "Sailed zig-zag course to use wind" , "Sailed zigzag course to take advantage of wind" .)