A bird - the female tailless one (5)
I believe the answer is:
heron
'a bird' is the definition.
(heron is a kind of bird)
'the female tailless one' is the wordplay.
'the female' becomes 'her' (I've seen this before**).
'tailless' means to remove the last letter.
'one' with its final letter removed is 'on'.
'her'+'on'='HERON'
(Other definitions for heron that I've seen before include "Large British wading bird" , "Wading bird with long neck and legs" , "Rhone (anag) - bird" , "Tall wading bird" , "Grey or white long-legged wading bird" .)