In plain words
Beginningless awareness, unborn and ancient, dwells always in the cave of one's own heart. It has no form, no world, no stain, no equal, no attachment. It cannot be thought, it cannot be seen, it cannot be taken hold of.
Word for word
Beginningless awareness, unborn and ancient, abides always in one's heart-cave, without form, world, stain, comparison or attachment, and cannot be conceived, seen or grasped as an object.