Problem with ring for kind of wrestling (4)
I believe the answer is:
sumo
'kind of wrestling' is the definition.
(I've seen this before)
'problem with ring' is the wordplay.
'problem' becomes 'sum' (arithmetic problem).
'with' says to put letters next to each other.
'ring' becomes 'o'.
'sum'+'o'='SUMO'
'for' is the link.
(Other definitions for sumo that I've seen before include "slappers fighting?" , "Jap. wrestling" , "Large Japanese wrestler" , "Traditional Japanese wrestling by fat men" , "Style of traditional Japanese wrestling" .)