Upsetting carer, it's unpredictable (7)
I believe the answer is:
erratic
'unpredictable' is the definition.
(synonyms)
'upsetting carer it's' is the wordplay.
'upsetting' indicates an anagram.
'carer'+'it'='carerit'
'carerit' is an anagram of 'ERRATIC'.
(Other definitions for erratic that I've seen before include "Not regular in pattern" , "Sporadic" , "on irregular path" , "Uneven in movement or quality" , "Irregular, capricious" .)