with a straight face (adverb) seriously: not humorously
Sinonime: actively, all joking aside, cool it, cut the comedy, determinedly,
down,
earnestly, fervently, for real, gravely, in all conscience, in all seriousness, in earnest,
intently,
passionately, purposefully, resolutely, sedately, simmer down,
sincerely, soberly, solemnly, sternly, straighten out, thoughtfully,
vigorously, with a straight face, with forethought, with sobriety, zealously
Antonime: funnily,
lightly