This English expression is used to describe a person that likes to drive fast. To make an excuse for their habit, they say they have a lead foot. In other words, their foot is made out of the type of metal, lead, which is very heavy. The weight of their foot causes them to put more pressure on the gas petal, and drive faster :)

Hear more of our English expressions at our website here: https://www.realenglishconversations.com/