Harold has time to stop (4)
I believe the answer is:
halt
'stop' is the definition.
(halt can mean to stop)
'harold has time' is the wordplay.
'harold' becomes 'Hal' (diminutive, as in Hal Prince).
'has' is a charade indicator (letters next to each other).
'time' becomes 't' (abbreviation).
'hal'+'t'='HALT'
'to' is the link.
(Other definitions for halt that I've seen before include "Stop or pause" , "Falter - stop" , "Pull up" , "limping" , "game" .)