One following quiet step (4)
I believe the answer is:
pace
'step' is the definition.
(I know that step can be written as pace)
'one following quiet' is the wordplay.
'one' becomes 'ace' (ace has a value of one in some card games).
'following' means one lot of letters go next to another.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'ace' put after 'p' is 'PACE'.
(Other definitions for pace that I've seen before include "Step or tempo" , "Clip" , "With the leave of; speed" , "Rate of progress" , "Speed of a single step?" .)