Yes. You'd expect "dangerous" to be some word like "pieczny", but in fact "dangerous" seems to be "niebezpieczny" :-)
EDIT: My biggest dictionary, the PWN Wielki Słownik, does show the word "piecza" which it marks as "literary" meaning "care" in the sense of looking after somebody. Maybe it's related to "pieczny*"
Polish language is constantly evolving (like others). Yes, "piecza" = "opieka" = care; mieć pieczę = opiekować się = take care.
robota = a work; bezrobotny = unemployed; where robotny = pracowity = hard-working. And employed = zatrudniony; employee = pracownik.
dusza = a soul; bezduszny = nieczuły = soulless / unfeeling; where duszny = stifling. And soulful = uduchowiony.
nadzieja = a soul; beznadziejny = hopeless; (there is no Polish word 'nadziejny'; where hopefull = pełen nadziei / obiecujący.
broń = a weapon; bezbronny = helpless; obronny = defensive; helpful = pomocny
Bóg = God; bezbożny = godless / ungodly; godly = pobożny
ceremoniał = etykieta = etiquette; bezceremonialny = nonszalancki = flippant; ceremonialny = obrzędowy = ceremonial
czelność = śmiałość = daring; bezczelny = shameless / insolent; shameful = haniebny
My favorite example regarding Polish adhesions is niebieski = blue. Before Christianity Slavic people had Slavic mythology. They believed that demons biesy lived on the earth / in the earth's abyss (e.g. rivers). So when we were taught about Christian God that lives in the sky in the Heaven we called it Niebiosa (probably then it was nie-biesy - the place without demons). The sky has blue color so: a sky = niebo, a Heaven = Niebo/Niebiosa; blue = niebieski (before, it was modry); heavenly = niebiański (then it was niebieski too). BTW. Księżyc means książę nocy - the prince of the night. I never read Sapkowski but probably a lot of his succes is thanks to Slavic mythology.