One often walked on after quiet sign of indifference (5)
I believe the answer is:
shrug
'sign of indifference' is the definition.
(a shrug indicates a lack of interest)
'one often walked on after quiet' is the wordplay.
'one often walked on' becomes 'rug' (rugs get walked over).
'after' means one lot of letters go next to another.
'quiet' becomes 'sh' ('sh' is used to tell someone to be quiet).
'rug' after 'sh' is 'SHRUG'.
(Other definitions for shrug that I've seen before include "Expressive shoulder movement" , "Sign of indifference" , "Expression of indifference" , "Show lack of concern" , "Dismissive gesture" .)