radical stimulus

impetus incentive motivation stimulant

adjuvant agitator enzyme goad impulse incendiary incitation incitement reactant reactionary spur synergist

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block hindrance

blockage preventer prevention

adjuvant agitator enzyme ferment goad impetus impulse incendiary incentive incitation incitement leaven motivation reactant reactionary spur stimulant synergist yeast

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block discouragement hindrance