the world > food and drink > food > consumption of food or drink > appetite > have (good) appetite [verb (transitive)] > sharpen appetite (2)
To make sharp or sharper (in various transferred and figurative senses of the adjective). Now… To render more acute (a person's wits, sight…
To sharpen, render (more) acute, keen, or eager (a person's wits, appetite, interest, curiosity, etc.). Also with up.