Apron (5)
(Other definitions for pinny that I've seen before include "Apron (abbr)" , "Apron (abbrev.)" , "Apron-like protective garment (abbreviated)" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">apron</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pinafore that I've seen before include "G&S ship" , "Sort of apron" , "Stagecraft, say" , "HMS -- (G&S)" , "'HMS - - ' G & S" .)