Hold up vessel carrying cereal product (8)
I believe the answer is:
brandish
'hold up' is the definition.
(thesaurus)
'vessel carrying cereal product' is the wordplay.
'vessel' becomes 'dish' ().
'carrying' is a charade indicator (letters next to each other) (in a down clue, the bottom letters carry others).
'cereal product' becomes 'bran' (I've seen this in another clue).
'dish' put after 'bran' is 'BRANDISH'.
(Other definitions for brandish that I've seen before include "Wave like a weapon" , "Wave something about threateningly" , "parade" , "Flourish aggressively" , "shake" .)