Banish cross page occupying overturned shelter (5)
I believe the answer is:
expel
'banish' is the definition.
(I've seen this before)
'cross page occupying overturned shelter' is the wordplay.
'cross' becomes 'x' (an X is a cross).
'page' becomes 'p'.
'occupying' means one lot of letters goes inside another (inserted letters occupy or enter the word).
'overturned' shows that the letters should be reversed in order.
'shelter' becomes 'lee' (as in lee side, the side sheltered from wind).
'lee' reversed gives 'eel'.
'x'+'p'='xp'
'xp' placed into 'eel' is 'EXPEL'.
(Other definitions for expel that I've seen before include "Possibly remove from club" , "Evict" , "Banish (undesirable alien?)" , "Remove from membership" , "Drive out with force" .)