Mo's coffee? (7)
I believe the answer is:
instant
This clue is a double definition.
'mo's' is the first definition.
(both can mean a short period of time)
'coffee?' is the second definition.
(instant coffee)
(Other definitions for instant that I've seen before include "Occurring with no delay" , "Mo" , "The blink of an eye" , "This coffee comes in powder form" , "Trice" .)