Erected for one party, large shelter (5)
I believe the answer is:
lodge
'shelter' is the definition.
(thesaurus)
'erected for one party large' is the wordplay.
'erected' is a reversal indicator (in a down clue, letters go up).
'for one' becomes 'eg' (both can mean 'for example').
'party' becomes 'do' (do is a kind of party).
'large' becomes 'L' (eg in clothes sizes).
'eg'+'do'+'l'='egdol'
'egdol' backwards is 'LODGE'.
(Other definitions for lodge that I've seen before include "Masonic association" , "British physicist" , "small house alongside park" , "Cabin for seasonal activity - become embedded" , "abode" .)