Briefly describes unpopular ranges (8)
I believe the answer is:
outlines
'briefly describes' is the definition.
'unpopular ranges' is the wordplay.
'unpopular' becomes 'out' (similar in meaning).
'ranges' becomes 'lines' ().
'out'+'lines'='OUTLINES'
(Other definitions for outlines that I've seen before include "Sketchy summaries of the main points" , "General principles" , "Sketches" , "Provides the main points without the details" , "Adumbrates" .)