pel/puls

drive; push

Spelled pel, puls · pellere 'drive, push, strike'; participial stem puls-

Latin pellere meant to drive: repel pushes back, propel pushes forward, and an impulse is a push toward action.

Words built from it

dispel — make a fear, doubt, or mistaken belief disappear
Latin dis- (apart) + pellere (drive) → dispellere → dispel
impulse — a sudden urge to act
Latin in- (into), assimilated to im- + pellere (push) → impellere → impulsus (a push) → impulse
compulsory — required; enforced by a rule or authority
Latin com- (intensively) + pellere (drive) → compellere (force) → compulsus → compulsory
repel — drive back or keep away
Latin re- (back) + pellere (drive) → repellere → repel
expulsion — the act of forcing someone or something out
Latin ex- (out) + pellere (drive) → expellere → expulsio (driving out) → expulsion
propel — push or drive forward
Latin pro- (forward) + pellere (drive) → propellere → propel
pulsate — beat or throb rhythmically
Latin pellere (strike, push) → pulsare (strike repeatedly) → pulsatus → pulsate

pellet — Comes through French pelote 'ball' from Latin pila 'ball,' not pellere 'push.'