Starchy cereal (4)
I believe the answer is:
sago
'starchy cereal' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sago that I've seen before include "Palm cereal" , "Powdery starchy food" , "Edible palm starch" , "Edible powdery starch" , "Powdery starch from a palm" .)