Gravely, soberly (8)
I believe the answer is:
solemnly
I believe this is a double definition.
'gravely' is the first definition.
(I've seen this before)
'soberly' is the second definition.
(thesaurus)
(Other definitions for solemnly that I've seen before include "Gravely and sedately" , "in formal and dignified way" , "In a formal and dignified manner" .)