End with jars upside down (4)
I believe the answer is:
stop
'end' is the definition.
(stopping is a kind of ending)
'jars upside down' is the wordplay.
'jars' becomes 'pots'.
'upside down' says the letters should be written backwards.
'pots' written backwards gives 'STOP'.
'with' is the link.
(Other definitions for stop that I've seen before include "cut out" , "Knock out" , "port of call" , "Refrain from" , "Plug - organ knob - bus halt - period" .)