Unlawfully, get Sri Lanka's opener out for a duck (4)
I believe the answer is:
teal
'duck' is the definition.
(teal is a kind of duck)
'unlawfully get sri lanka's opener out for a' is the wordplay.
I cannot really see how this works, but
'a' is found in the answer.
The remaining letters 'tel' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
(Other definitions for teal that I've seen before include "Raise (subject matter)" , "Variety of duck" , "Dark green-blue; duck" , "Bluish shade of green" , "Duck - dark greenish-blue" .)