Seep/siːp/ Definition 1 of 2Pro Tip 1/3Physical Movement Imagine liquid moving slowly through tiny spaces, like a sponge absorbing water. Oil seeped through the tiny cracks in the rock. Pro Tip 2/3Gradual Effect Think of how something builds up or worsens over time, like rust on metal. Dampness seeped into the walls, causing mold. Pro Tip 3/3Invisible Process Seep often refers to movement that is not immediately obvious or visible to the eye. Fear slowly seeped into her heart.