i Register
In some senses, sombre is marked as obsolete, UK. Watch for register when choosing this word.
VERBS
be, look, seem
The sky seemed sombre and grey as rain began to fall.
become, grow
The atmosphere in the room became sombre after they heard the bad news.
remain
Despite the good news, her expression remained sombre throughout the meeting.
ADV
very
fairly, rather, somewhat
The office atmosphere was rather sombre after the company announced the layoffs.
suitably
The old church was decorated in suitably sombre colours for the memorial service.