Beer seen outside South Africa game usually (2,1,4)
I believe the answer is:
as a rule
'usually' is the definition.
(I've seen this before)
'beer seen outside south africa game' is the wordplay.
'beer' becomes 'ale' (I've seen this before).
'seen outside' means one lot of letters goes inside another.
'south africa' becomes 'sa' (abbreviation).
'game' becomes 'ru' (rugby union).
'sa'+'ru'='saru'
'ale' going around 'saru' is 'AS A RULE'.
(Other definitions for as a rule that I've seen before include "Under normal circumstances" , "how one might take a calibrated rod" , "Usually but not always" , "Usually, in the normal course" , "Most of the time" .)