Sea-eagle (4)
I believe the answer is:
erne
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sea-eagle</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for erne that I've seen before include "Sea bird: lough in Ulster" , "White-tailed eagle" , "'Sea-eagle, river and lough (4)'" , "European sea eagle" , "Irish river, loughs; sea bird" .)