Very upper-class male gets into wrestling (4)
I believe the answer is:
sumo
'wrestling' is the definition.
(I know that sumo is a type of wrestling)
'very upper-class male gets' is the wordplay.
'very' becomes 'so' (both can mean 'extremely').
'upper-class' becomes 'u' (similar in meaning).
'male' becomes 'm' (common abbreviation).
'gets' is an insertion indicator.
'u'+'m'='um'
'so' placed around 'um' is 'SUMO'.
'into' is the link.
(Other definitions for sumo that I've seen before include "Japanese form of wrestling" , "Large Japanese wrestler" , "Japanese wrestling for huge men" , "Kind of wrestling" , "one of the martial arts" .)