Popular hospital room lately vacated secretly (8)
I believe the answer is:
inwardly
'secretly' is the definition.
(I've seen this before)
'popular hospital room lately vacated' is the wordplay.
'popular' becomes 'in' ('in' can mean trendy).
'hospital room' becomes 'ward' (I've seen this before).
'vacated' suggests removing the centre (internal letters vacate the word).
'lately' with its middle removed is 'ly'.
'in'+'ward'+'ly'='INWARDLY'
(Other definitions for inwardly that I've seen before include "to the centre" , "Mentally or spiritually" , "In the heart, privately" , "secretly" .)