"Science Friday" host Flatow (3)
I believe the answer is:
ira
'science friday host flatow' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ira that I've seen before include "Illegal organisation, initially" , "nationalists" , "Brother of George Gershwin" , "terrorists" , "Illegal organisation, in short" .)