Swede's routine appropriate for adoption by wannabe teetotallers (8)
I believe the answer is:
rutabaga
'swede's' is the definition.
(synonyms)
'routine appropriate for adoption by wannabe teetotallers' is the wordplay.
'routine' becomes 'rut' (rut is a kind of routine).
'appropriate' becomes 'bag' (I've seen this in other clues).
'for adoption by' means one lot of letters goes inside another.
'wannabe teetotallers' becomes 'AA' (short for Alcoholics Anonymous).
'bag' put into 'aa' is 'abaga'.
'rut'+'abaga'='RUTABAGA'
(Other definitions for rutabaga that I've seen before include "American term for swede" , "vegetable in America" , "US term for swede" , "Swede; tuba raga (anag.)" .)