Make an oopsie (4)
(Other definitions for slip that I've seen before include "Lingerie item - fielding position" , "Glide; petticoat" , "Strip" , "Minor mistake - undergarment" , "potter has to cover?" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">make an oopsie</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 err that I've seen before include "Make mistake in Canberra" , "Go astray" , "Drop a clanger" , "Miss the mark" , "Leave the straight and narrow" .)