Put the tip of your index or middle finger against the pad of your thumb and flick it. You have just executed the original meaning of the word “fillip.” This word is likely an onomatopoeia — it appeared in the mid-16th century around the same time as the words “flip” and “flirt.” Over time, the word evolved; as a noun it can refer to a boost or stimulus, and as a verb, it can mean “to flick something with a finger,” “to strike something sharply,” and “to stimulate/urge someone or something.” For example, “The doctor asked the patient a series of questions in an attempt to fillip her memory, but all she could do in response was fillip the table.”