To have a sweet tooth is to have a strong liking for sugary food, whether that means cakes, sweets, chocolate or puddings. It is usually said lightly, as a way of explaining why someone can never resist a dessert menu or keeps a tin of biscuits within reach. The “tooth” in the phrase has nothing to do with dentistry: it stands for taste or appetite, so a sweet tooth is really a taste for sweetness rather than a particular kind of tooth.
What’s the origin of the phrase ‘a sweet tooth’?
The phrase is old enough that its structure reflects a sense of “tooth” that has since dropped out of everyday English. From the late fourteenth century, “tooth” could mean a taste or liking for something, quite apart from the tooth in your mouth, and “swete toth” is recorded in that period as meaning a fondness for sugary food. This fits with the related word “toothsome”, meaning appetising, which preserves the same old sense of tooth as taste.
Popular accounts of the phrase often point to Geoffrey Chaucer, citing a line near the end of the Wife of Bath’s Prologue in The Canterbury Tales that is usually quoted in modernised wording along the lines of “But I will keep it for your own sweet tooth.” Since this circulates in updated spelling rather than as a verified original-text citation, it should be taken as illustrative of the phrase’s early currency rather than as a precisely dated first use. Some sources instead push the phrase’s origin forward to 1611, crediting Thomas Nashe’s The Choise of Valentines. That attribution cannot be right as stated: Nashe died in about 1601, and The Choise of Valentines was written in the early 1590s, so no work of his can carry a 1611 date. Even setting the date aside, a late-sixteenth-century use would still fall some two centuries after the recorded fourteenth-century form, making it a later appearance rather than a true starting point.
Whatever the exact first instance, the phrase reads in later use as an unremarkable, familiar expression rather than a novelty, which suggests something already in circulation for generations rather than freshly coined, consistent with a metaphorical sense of “tooth” that stretches back to Chaucer’s own lifetime.