Cartier's work is unpredictable (7)
I believe the answer is:
erratic
'unpredictable' is the definition.
(synonyms)
'cartier's work' is the wordplay.
'work' indicates an anagram.
'cartier' is an anagram of 'ERRATIC'.
'is' acts as a link.
(Other definitions for erratic that I've seen before include "Irregular, not dependable" , "Irregular in pattern or movement" , "Irregular or uneven in movement or habit" , "Uneven in movement or quality" , "Fluctuating" .)