Caper around about outside new model one (5)
I believe the answer is:
antic
'caper' is the definition.
(synonyms)
'around about outside new model one' is the wordplay.
'around' becomes 'c' (abbreviation for 'circa').
'about' is a charade indicator (letters next to each other).
'outside new model one' becomes 'anti' (I can't justify this - if you can you should believe this answer much more).
'c' put after 'anti' is 'ANTIC'.
Can you help me to learn more?
(Other definitions for antic that I've seen before include "Playful caper" , "Mad act done for fun" , "Eccentric once" , "Prank" , "Caper, trick" .)