Beast in man? I'm a lady! (6)
I believe the answer is:
animal
'beast' is the definition.
(giraffe is a type of animal)
'in man? i'm a lady' is the wordplay.
'in' indicates a hidden word.
'ANIMAL' is hidden in the letters of 'man im a lady'.
(Other definitions for animal that I've seen before include "savage" , "Mammal" , "cat, perhaps" , "Animate being" , "Man or beast" .)