Long and nasty duel outside a broken-down bar (7)
I believe the answer is:
durable
'long' is the definition.
(similar in meaning)
'nasty duel outside a broken-down bar' is the wordplay.
'nasty' is an anagram indicator.
'outside' is an insertion indicator.
'a broken down' indicates anagramming the letters.
'duel' anagrammed gives 'dule'.
'bar' is an anagram of 'rab'.
'dule' enclosing 'rab' is 'DURABLE'.
'and' is the link.
(Other definitions for durable that I've seen before include "Lasting a long time" , "existing for a long time" , "Long-lasting and hard-wearing" , "Rugged; long-lasting" , "Firm" .)