Cosy retreat (4)
I believe the answer is:
nest
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cosy retreat</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 nest that I've seen before include "Structure to lay eggs" , "Rook's residence?" , "A set (of tables)" , "Roost" , "Bird's retreat" .)