Sneering Sam acquiring fancy cars (7)
I believe the answer is:
sarcasm
'sneering' is the definition.
(thesaurus)
'sam acquiring fancy cars' is the wordplay.
'acquiring' is an insertion indicator.
'fancy' indicates anagramming the letters.
'cars' with letters rearranged gives 'rcas'.
'sam' enclosing 'rcas' is 'SARCASM'.
(Other definitions for sarcasm that I've seen before include "Harsh or bitter derision or irony" , "Scornful attitude" , "Insulting irony" , "Show of ironic contempt" , "Insulting lingo" .)