most serious

deliberate genuine honest severe sincere thoughtful

sober

austere bound bound and determined businesslike cold sober contemplative deadpan determined downbeat earnest funereal go for broke grave grim intent long-faced meditative no-nonsense pensive pokerfaced reflective resolute resolved sedate set solemn staid steady stern unhumorous unsmiling weighty

deceptive dishonest false insincere misleading untrustworthy

flippant funny happy light minor trivial unimportant unserious

dangerous deep difficult far-reaching grievous important major meaningful severe significant tough urgent

arduous fateful fell formidable grave grim hard heavy laborious meaning business menacing momentous no joke no laughing matter of consequence operose out for blood playing hard ball pressing smoking sobering strenuous strictly business threatening ugly unamusing unhumorous worrying

calm easy facile friendly insignificant little meaningless minor small trivial unimportant worthless

flippant funny happy light unserious