I left serious old building without perfume (9)
I believe the answer is:
odourless
'without perfume' is the definition.
('perfume' can be 'odour' (I've seen this before) so maybe 'without perfume' can be ''odourless')
'i left serious old building' is the wordplay.
'left' is a deletion indicator.
'building' indicates anagramming the letters.
'serious'+'old'='seriousold'
'seriousold' with 'i' removed is 'serousold'.
'serousold' anagrammed gives 'ODOURLESS'.
(Other definitions for odourless that I've seen before include "Unscented" , "Without smell" , "without bouquet" , "devoid of smell" , "having no hint of whiff" .)