Impressed and serious during final (8)
I believe the answer is:
engraved
'impressed' is the definition.
(thesaurus)
'serious during final' is the wordplay.
'serious' becomes 'grave' ('grave' can be a synonym of 'serious').
'during' is an insertion indicator.
'final' becomes 'end' ('end' can be a synonym of 'final').
'grave' going within 'end' is 'ENGRAVED'.
'and' acts as a link.
(Other definitions for engraved that I've seen before include "Carved into surface" , "Cut or impressed into a surface" , "deeply impressed" , "Cut, carved (a design)" .)