The term 'seep through' can be described by two crossword solutions: OSMOSE (6 letters) and OOZE (4 letters). OSMOSE is a process in which molecules of a substance diffuse through a semipermeable membrane from a region of higher concentration to a region of lower concentration. OOZE is a slow, steady flow of a liquid or a soft, viscous material. Both terms describe the gradual passage of a substance through a porous surface.