serious (adjective) serious: somber, humorless
Sinonime: austere,
bound, bound and determined, businesslike, cold sober,
contemplative, deadpan,
deliberate,
determined, downbeat,
earnest, funereal,
genuine, go for broke,
grave,
grim,
honest,
intent, long-faced, meditative, no-nonsense,
pensive, pokerfaced,
reflective,
resolute, resolved,
sedate,
set,
severe,
sincere,
sober,
solemn,
staid,
steady,
stern,
thoughtful, unhumorous, unsmiling, weighty
Antonime: flippant,
funny,
happy,
light