South American greeting Japanese dish (5)
I believe the answer is:
sushi
'japanese dish' is the definition.
(type of Japanese food)
'south american greeting' is the wordplay.
'south' becomes 's' (abbreviation).
'american' becomes 'US' (United States).
'greeting' becomes 'hi' (hi is a kind of greeting).
's'+'us'+'hi'='SUSHI'
(Other definitions for sushi that I've seen before include "Asian dish" , "Japanese rice-based dish" , "Cold rice balls with raw fish" , "Japanese cold rice dish" , "Oriental food" .)