Popular, outwardly ethereal holiday venue (5)
I believe the answer is:
hotel
'holiday venue' is the definition.
(I've seen this before)
'popular outwardly ethereal' is the wordplay.
'popular' becomes 'hot' (hot can mean popular or trendy).
'outwardly' says to hollow out the word (remove centre letters) (only the outermost letters are used).
'ethereal' with its centre removed is 'el'.
'hot'+'el'='HOTEL'
(Other definitions for hotel that I've seen before include "It keeps guests" , "Holiday venue" , "Letter transmitted" , "sleeper" , "Travel accommodation" .)