Tessa returned something valuable (5)
I believe the answer is:
asset
'something valuable' is the definition.
(I've seen this before)
'tessa returned' is the wordplay.
'returned' is a reversal indicator.
'tessa' reversed gives 'ASSET'.
(Other definitions for asset that I've seen before include "Plus point" , "Anything of value" , "Item well worth having" , "Item conferring advantage" , "A thing of value" .)