Adjectives

(s)drowsy, drowsing, dozyhalf asleep“made drowsy by the long ride”, “it seemed a pity to disturb the drowsing (or dozing) professor”, “a tired dozy child”, “the nodding (or napping) grandmother in her rocking chair”
(s)drowsy, oscitant, yawningshowing lack of attention or boredom“the yawning congregation”