Mushy peas entertaining old story-teller (5)
I believe the answer is:
aesop
'story-teller' is the definition.
(I've seen this before)
'mushy peas entertaining old' is the wordplay.
'mushy' indicates anagramming the letters (letters mushed up).
'entertaining' indicates putting letters inside (inviting in, as for dinner).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'peas' is an anagram of 'aesp'.
'aesp' enclosing 'o' is 'AESOP'.
(Other definitions for aesop that I've seen before include "story teller" , "A pose by Greek writer of fables" , "So ape the writer of fables" , "fabulous figure?" , "Classic fable writer" .)