Such a towering figure in the field of linguistics, politics and philosophy of psychology. Especially his linguistics work was something I found personally extremely engaging as a student. Reading his review of B.F. Skinner's book was a highlight of my philosophy of psychology class.
I know he has been active since the turn of the century but his influence was definitely more of a 20th century phenomenon. Not many academics reach the level of popular awareness that he did.
For you yongsters out there, Chomsky vs Skinner was the original Kendrick Lamar vs Drake.