Bell cracked by a US art critic? (12)
I believe the answer is:
caricaturist
'bell' is the definition.
(Steve Bell is a Guardian cartoonist)
'cracked by a us art critic?' is the wordplay.
'cracked' is an anagram indicator.
'by' means one lot of letters go next to another.
'a'+'us'+'art'='ausart'
'ausart' put after 'critic' is 'criticausart'.
'criticausart' is an anagram of 'CARICATURIST'.
(Other definitions for caricaturist that I've seen before include "Job sketching exaggerated facial features" , "Comic cartoonist" , "Steve Bell, for example" , "Artist producing comic portraits" , "One who lampoons" .)