Strong, or possibly broken (6)
I believe the answer is:
robust
'strong' is the definition.
(associated in meaning)
'or possibly broken' is the wordplay.
'possibly' indicates anagramming the letters.
'broken' becomes 'bust' (I've seen this before).
'or' anagrammed gives 'ro'.
'ro'+'bust'='ROBUST'
(Other definitions for robust that I've seen before include "Down-to-earth" , "Well-built" , "Rugged and sturdy" , "Full and rich (wine)" , "Sturdy, resilient" .)