Vegetable makes Rita squirm and splutter (9)
I believe the answer is:
artichoke
'vegetable' is the definition.
(type of vegetable)
'rita squirm and splutter' is the wordplay.
'squirm' indicates anagramming the letters (I've seen 'squirming' mean this (I've seen this in other clues)).
'and' is a charade indicator (letters next to each other).
'splutter' becomes 'choke' (I can't justify this - if you can you should give a lot more credence to this answer).
'rita' with letters rearranged gives 'arti'.
'arti'+'choke'='ARTICHOKE'
'makes' acts as a link.
Can you help me to learn more?
(Other definitions for artichoke that I've seen before include "Globe vegetable?" , "See 26" , "Edible thistle-like bud" , "vegetable's served?" , "Vegetable could give you a thicko ear" .)