sternest (adjective) stern: serious, authoritarian
Sinonime: ascetic, astringent,
austere,
bitter, bullheaded, by the book,
cruel, disciplinary, dyed-in-the-wool, flinty, forbidding, frowning,
grim, hang-tough,
hard, hard-boiled, hard-core, hard-line, hard-nosed, hard-shell, hardheaded,
harsh,
implacable,
inexorable,
inflexible, mortified, mulish,
relentless,
rigid,
rigorous,
rough,
severe, steely, stiff-necked,
strict,
stubborn,
tough,
unrelenting, unsparing,
unyieldingAntonime: cheerful,
funny,
lenient,
light, smiling,
tolerant