It's a little one, darling (4)
I believe the answer is:
baby
I believe this is a double definition.
'it's a little one' is the first definition.
(thesaurus)
'darling' is the second definition.
(thesaurus)
(Other definitions for baby that I've seen before include "Timid person; very small" , "about to howl?" , "Very small (version)" , "Darling" , "Honey" .)