Whack (4)
(Other definitions for sock that I've seen before include "One going into Oxford maybe" , "Hit; horse's leg marking" , "Very short stocking?" , "impact" , "Hit with a powerful blow" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">whack</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 swat that I've seen before include "Crush (eg, a fly)" , "deliver blow" , "Hit a wasp or fly" , "Strike sharply (at fly?)" , "'Twas quite a smack" .)