Cliché light in weight; [of cakes and pastries] delicate and airy. (*Also: as ~.) Carrying Esther from the car to the house was no problem; she was as light as a feather.What a delicious cake, Tom! And light as air, too.
Extremely lightweight. This simile can be used to refer either to physical weight, as in This load is light as a feather, or to texture, as in This cake is light as a feather. [Mid-1500s]