Appetite/ˈæpɪtaɪt/ Definition 1 of 3Pro Tip 1/2Physical Need 'Appetite' often refers to a physical need. It can fluctuate based on time of day and activity level. After the hike, my appetite was huge. Pro Tip 2/2Idiomatic Expressions 'Appetite' is used in idioms like 'whet your appetite', meaning to increase interest or desire. The preview whetted my appetite for the full movie.