Injured climber, a top becoming tricky (11)
I believe the answer is:
problematic
'tricky' is the definition.
(thesaurus)
'injured climber a top' is the wordplay.
'injured' is an anagram indicator.
'climber'+'a'+'top'='climberatop'
'climberatop' anagrammed gives 'PROBLEMATIC'.
'becoming' is the link.
(Other definitions for problematic that I've seen before include "Baffling" , "Troublesome" , "Difficult; doubtful" , "Presenting difficulties" , "tricky" .)