Reportedly start race for ingredient (4)
I believe the answer is:
sago
'race for ingredient' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'reportedly start' is the wordplay.
'reportedly' becomes 'sa' (I am not sure about this - if you are sure you should believe this answer much more).
'start' becomes 'go' (synonyms).
'sa'+'go'='SAGO'
Can you help me to learn more?
(Other definitions for sago that I've seen before include "Starchy grain used in desserts" , "Starchy pudding cereal" , "Powdery starchy food" , "Edible palm starch" , "Edible powdery starch" .)