Proto-IE: *(s)kreit-
Meaning: trembling, fever
Celtic: *krit-, *skrit- > MIr crith `Zittern, Fieber'; Cymr cryd `Wiege, Fieber', ysgryd `von Furcht zittern', Corn scruth `von Furcht zittern', Bret skrija `von Furcht zittern'
Russ. meaning: дрожь, лихорадка
References: WP II 568 f