profound

adjective

1. 1

   situated at or extending to great depth; too deep to have been sounded or plumbed

   the profound depths of the sea

   the dark unfathomed caves of ocean"-Thomas Gray

2. 2

   (of sleep) deep and complete

   a heavy sleep

   fell into a profound sleep

3. 3

   coming from deep within one

   a profound sigh

4. 4

   of the greatest intensity; complete

   a profound silence

   a state of profound shock

5. 5

   showing intellectual penetration or emotional depth

   the differences are profound

   a profound insight

6. 6

   far-reaching and thoroughgoing in effect especially on the nature of something

   the fundamental revolution in human values that has occurred

   the book underwent fundamental changes