Blunder about Irish beast (7)
I believe the answer is:
giraffe
'beast' is the definition.
(giraffes are animals)
'blunder about irish' is the wordplay.
'blunder' becomes 'gaffe' (gaffe is a kind of blunder).
'about' indicates putting letters inside.
'irish' becomes 'IR' (abbreviation).
'gaffe' enclosing 'ir' is 'GIRAFFE'.
(Other definitions for giraffe that I've seen before include "Long-necked animal" , "African native ruminating" , "Tallest beast" , "Tallest living quadruped" , "Tallest extant quadruped" .)