Prom night vehicle (4)
I believe the answer is:
limo
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">prom night vehicle</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for limo that I've seen before include "Set of rooms" , "Luxurious car (colloq.)" , "vehicle" , "Stretched car (abbr)" , "Large luxurious car" .)