Genius sheep raised in pig pen (6)
I believe the answer is:
smarty
'genius sheep raised in pig pen' is the definition.
I can't judge whether this definition defines the answer.
'sheep raised in pig pen' is the wordplay.
'sheep' becomes 'ram' (male sheep).
'raised' shows that the letters should be reversed in order (going up in a down clue).
'in' means one lot of letters goes inside another.
'pig pen' becomes 'sty' (where pigs are kept).
'ram' written backwards gives 'mar'.
'mar' put within 'sty' is 'SMARTY'.
Can you help me to learn more?
(Another definition for smarty that I've seen is " So Alec".)