Piggish to hold up prickly character (9)
I believe the answer is:
porcupine
'prickly character' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'piggish to hold up' is the wordplay.
'piggish' becomes 'porcine' (synonyms).
'to hold' indicates putting letters inside.
'porcine' enclosing 'up' is 'PORCUPINE'.
Can you help me to learn more?
(Other definitions for porcupine that I've seen before include "it has sharp protrusions" , "One pointedly protected" , "there are many points in one's defence" , "Rodent with sharp black-and-white spikes" , "Rodent covered in protective spines" .)