1) Acutely 2) Badly 3) Critically 4) Dangerously 5) Fatally 6) How bad news may be given 7) In a grave and sober manner 8) Soberly 9) Solemnly 10) Staidly 11) To a severe or serious degree 12) With a straight face 1) Badly 2) Seriously 3) Severely 4) Sincerely 5) Soberly 6) Solemnly 7) Sombrely 8) Staidly 
• (adv.) In a grave manner.
Grave'ly adverb In a grave manner. 
[adv] - in a grave and sober manner
soberly adverb in a grave and sober manner; `he walked soberly toward the altar`