Getting bigger, King George: one defined by his appetite? (7)
I believe the answer is:
greater
'getting bigger king' is the definition.
I can't judge whether this defines the answer.
'george one defined by his appetite?' is the wordplay.
'george' becomes 'gr'.
'one defined by his appetite?' becomes 'eater' (someone who eats).
'gr'+'eater'='GREATER'
(Other definitions for greater that I've seen before include "More grand" , "Less small" , "More significant" , "More extensive" , "of more importance" .)