Speak or eat, possibly (5)
I believe the answer is:
orate
'speak' is the definition.
(I know that orate is a more specific form of the action speak)
'or eat possibly' is the wordplay.
'possibly' indicates an anagram.
'eat' anagrammed gives 'ate'.
'or'+'ate'='ORATE'
(Other definitions for orate that I've seen before include "Make a formal address" , "Make a flowery speech" , "Speaker may" , "Speak in florid style" , "Pontificate" .)