Keep going for Just a Minute (4,2)
I believe the answer is:
hold on
'just a minute' is the definition.
(both are used to tell someone to a wait a moment)
'keep going' is the wordplay.
'keep' becomes 'hold' (both can mean to have or possess something).
'going' becomes 'on' (both can mean functioning or activated).
'hold'+'on'='HOLD ON'
'for' acts as a link.
(Other definitions for hold on that I've seen before include "Informally, just a mo', or don't let go" , "Cling to - or stop right there" , "Cling to or informally stop a mo'" , "Keep one's grasp or maintain telephone contact" , "Wait a moment - cling firmly" .)