Continuously (5)
(Other definitions for nonstop that I've seen before include "(Of a flight) direct" , "Without halting" , "done without interruption" , "Going straight from A to B" , "Never-ending" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">continuously</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 onend that I've seen before include "Continuously" , "erect" .)