SLIP (IN) is a term that can be used in two different contexts. The first context is a verb, meaning to move quickly and quietly, often without being noticed. The second context is a noun, referring to a thin piece of material used to protect surfaces from damage or wear. The crossword solutions for this term are SEEP (4 letters) and OOZE (4 letters). SEEP is a verb meaning to slowly pass through a porous surface or substance, while OOZE is a verb meaning to flow or leak out slowly.