Of little width (6)
I believe the answer is:
narrow
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">of little width</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 narrow that I've seen before include "With sides close together" , "Short of breadth" , "Restrict" , "Strait or confined" , "Of limited width" .)