A pose as a fabulist (5)
I believe the answer is:
aesop
'a fabulist' is the definition.
(Greek composer of fables)
'a pose' is the wordplay.
'a pose' anagrams to 'AESOP'.
But, I'm not sure how the anagram is indicated.
'as' is the link.
Can you help me to learn more?
(Other definitions for aesop that I've seen before include "satirical writer" , "fabulous figure?" , "A classical fable teller" , "Ancient Greek author of moral tales" , "very old writer" .)