Bird almost out of breath? (6)
I believe the answer is:
puffin
'bird' is the definition.
(puffin is a kind of bird)
'almost out of breath?' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'out of breath?' becomes 'puffing' (I've seen this in another clue).
'puffing' with its last letter taken off is 'PUFFIN'.
(Other definitions for puffin that I've seen before include "diver" , "Bird with colourful beak" , "Seabird (breathin' heavily?)" , "Bright-billed bird" , "Large-beaked sea bird" .)