Darkening rhymes with:
awakening, beckoning, blackening, chickening, dekoning, likening, quickening, reawakening, reckoning, sickening, slackening, thickening, weakening, wilkening
Darkening sounds like:
darkness, dierking, dorgan's, drachmas, dragging, dragon's, dragons, dressing, dressings, drowsiness, drugging, durkheim's