As adverbs the difference between solemnly and gravely
is that solemnly is in a solemn manner while gravely is in a grave or serious manner.
As an adjective gravely is
characterised by gravel, pebbles, or small stones.
gravely
English
Etymology 1
From (etyl) (m), (m), equivalent to .
Adjective
(
en adjective)
Characterised by gravel, pebbles, or small stones.
Etymology 2
Adverb
(
en adverb)
In a grave or serious manner.