Biweekly

codwutygodniowy

(occurring every two weeks)

copółtygodniowy

(occurring twice a week)

dwutygodniowy

(occurring every two weeks)

codwutygodniowo

(every two weeks)

copółtygodniowo

(twice a week)

dwa razy na tydzień

(twice a week)

dwa razy w tygodniu

(twice a week)

dwutygodniowo

(every two weeks)

dwutygodnik

(something published or released once every two weeks)