a) In soil mechanics or geotechnical engineering, creep refers to the process of slow deformation of saturated material occurring under a constant effective stress, usually after the deformation in response to loading and/or to pore water pressure changes. For clays, if the pore water in the clay is allowed to escape, then the process is drained creep; if the pore water of the clay is confined, then it is undrained creep.

b) In geological sciences, creep is the very slow downslope movement of material.
Cf., secondary compression.