A little European larva (7)
I believe the answer is:
tadpole
'larva' is the definition.
(I know that tadpole is a type of larva)
'a little european' is the wordplay.
'a little' becomes 'tad' (both can mean a small amount).
'european' becomes 'pole' (someone from Poland).
'tad'+'pole'='TADPOLE'
(Other definitions for tadpole that I've seen before include "Aquatic larva of toads and frogs" , "Old tape (anag.)" , "Baby amphibian" , "developed from spawn" , "Young amphibian" .)