Traffic jam (5-2)
I believe the answer is:
snarl-up
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">traffic jam</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for snarl-up that I've seen before include "Traffic jam (colloq.)" , "Traffic jam; muddle" .)