Embryonic frog (7)
I believe the answer is:
tadpole
'embryonic frog' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tadpole that I've seen before include "Old tape (anag.)" , "youngster" , "Baby amphibian" , "immature sea squirt" , "Aquatic larva of toads and frogs" .)