Preserve order initially, drunk among native Americans (8)
I believe the answer is:
creosote
'preserve' is the definition.
(creosote can be used as a preservative)
'order initially drunk among native americans' is the wordplay.
'initially' indicates taking the first letters.
'drunk' becomes 'sot' (both can mean someone who drinks too much).
'among' is an insertion indicator.
'native americans' becomes 'cree' (I've seen this in other clues).
The first letter of 'order' is 'o'.
'o'+'sot'='osot'
'osot' placed within 'cree' is 'CREOSOTE'.
(Other definitions for creosote that I've seen before include "'Dark oily liquid, preserves wood (8)'" , "Preservative liquid obtained from coal tar" , "Wood treatment" , "Dark oily liquid, preservative for wood" , "Oily liquid obtained from tar" .)