Meths or rum container (7)
I believe the answer is:
thermos
'container' is the definition.
(thermos is a kind of container)
'meths or rum' is the wordplay.
'rum' indicates an anagram (rum can mean strange or unusual).
'meths'+'or'='methsor'
'methsor' is an anagram of 'THERMOS'.
(Other definitions for thermos that I've seen before include "Vacuum flask for mothers" , "Container to retain heat" , "Flask trade mark" , "Heat-retaining flask for mothers" .)