Inverted or broken strapping (6)
I believe the answer is:
robust
'strapping' is the definition.
('robust' can be similar in meaning to 'strapping')
'inverted or broken' is the wordplay.
'inverted' says the letters should be written in reverse.
'broken' becomes 'bust' (I've seen this before).
'or' in reverse letter order is 'ro'.
'ro'+'bust'='ROBUST'
(Other definitions for robust that I've seen before include "Strong and healthy" , "Hardy and vigorous" , "Physically strong" , "Sturdily built" , "Unlikely to break" .)