8a Many a luminary these times is deceased. (4)
11a Inordinate need to indicate. (6)
18a Fall to spring perpetually... as noses twitching annually? (8,7)
28a The brain behind the brainiest quiz. (10)
1d Measure of a matriarch - at 16 a tormentor! (10)
7d Dethrone such villainous tyrants. (4)
19d Sounds like they've no skill, but they're top of the class! (8)