Small program secures vehicle proverbially easy to topple (9)
I believe the answer is:
applecart
'proverbially easy to topple' is the definition.
I can't tell whether this defines the answer.
'small program secures vehicle' is the wordplay.
'small program' becomes 'applet' (I've seen this in another clue).
'secures' is an insertion indicator.
'vehicle' becomes 'car' (car is a kind of vehicle).
'applet' going around 'car' is 'APPLECART'.
Can you help me to learn more?
(Other definitions for applecart that I've seen before include "this could be upset" , "Fruit carrier, often upset" , "To upset this is to throw plans into confusion" , "Spoil carefully laid plans - upset the . . . . . . . . ." , "Upset this fruit carrier to spoil plans" .)