Primarily used for big holes, caves, and caverns, holes which do not go all the way through the object. For small holes of this type, use lehup. For holes that go all the way through, use chekullk for large holes and chekulk for small holes.
Llehup/lehup as nouns are interchangeable with kwellhup/kwelhup.
This word is labeled as a noun in the Barona dictionary but seems to behave like a verb. In Mesa Grande dictionary it is defined as "is a big hole in the ground, cave", and it has nominalized forms kullhup or kwellhup, simply meaning "hole". Perhaps llehup (llehuup) was originally a verb meaning "has a (big) hole in it". Further investigation is needed to validate this hypothesis.