1. (extreme plainness)
surowość
synonim: austereness
synonim: severity

2. (used of the degree of something undesirable e.g. pain or weather)
dotkliwość: : synonim: badness
synonim: severity

3. (excessive sternness
"severity of character"
"the harshness of his punishment was inhuman"
"the rigors of boot camp")
surowość, srogość: : synonim: severity
synonim: harshness
synonim: rigor
synonim: rigour
synonim: rigorousness
synonim: rigourousness
synonim: inclemency
synonim: hardness
synonim: stiffness