Anaesthetised foot has feeling but it's lowering (8)
I believe the answer is:
demotion
'it's lowering' is the definition.
(I have seen 'Lowering of rank ' mean 'demotion' so perhaps 'lowering' could also mean 'demotion')
'anaesthetised foot has feeling' is the wordplay.
'foot' says to take the final letters (in a down clue, the bottom letter).
'has' says to put letters next to each other.
'feeling' becomes 'emotion' (emotion is a kind of feeling).
The last letter of 'anaesthetised' is 'd'.
'd'+'emotion'='DEMOTION'
'but' acts as a link.
(Other definitions for demotion that I've seen before include "The putting down" , "Relegation" , "Going down" , "Motioned about reduction in rank" , "A lowering in rank or position" .)