Rugged mountain range (6)
I believe the answer is:
sierra
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rugged mountain range</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 sierra that I've seen before include "that Romeo is not after" , "Long jagged mountain chain" , "Jagged mountain range" , "Jagged mountains - code word for S" , "- Nevada, Spanish mountain range" .)