Small pistol (4)
(Other definitions for colt that I've seen before include "Youngster" , "Mount" , "runner" , "Rod" , "Early American revolver" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">small pistol</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 derringer that I've seen before include "Small pistol used by gamblers in western films" , "Pocket pistol" , "Weapon" , "Short-barrelled American pistol" .)