noun

something which acts as a stimulus or boost to an activity.

the halving of car tax would provide a fillip to sales

stimulus,stimulation,stimulant,boost,encouragement,incitement,incentive,impetus,inducement,motivation,tonic,uplift,lift,reviver,spur,goad,prod,push,prompt,aid,help,shot in the arm,pick-me-up

verb

propel (a small object) with a flick of the fingers.