They cover cold cereal (5)
I believe the answer is:
coats
'they cover' is the definition.
Although both the answer and 'cover' are verbs, they are not in the same form of the verb.
'cold cereal' is the wordplay.
'cold' becomes 'C' (eg on taps).
'cereal' becomes 'oats' (type of cereal).
'c'+'oats'='COATS'
Can you help me to learn more?
(Other definitions for coats that I've seen before include "Layers" , "Outdoor garments" .)