Edmonton athlete (5)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">edmonton athlete</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for oiler that I've seen before include "Loire (anag.)" , "One applying lubricant" , "Device that lubricates" , "Fuel tanker" , "Ship" .)