Filed from 2 published puzzles

TEAMSTERS

Set to 2 different clues across 2 published puzzles, most often “Semi professionals?” — The New York Times, Friday, 5 March 2010.

9 letters

Every clue on record, most used first

Semi professionals?once
The New York Times — Friday, 5 March 2010
Driving force?once
The New York Times — Saturday, 20 November 1999

Other answers to these clues

IMPETUS7 letters
IMPULSE7 letters
MOTOR5 letters
URGE4 letters