profound

From Wiktionary

Adjective[change]

Positive
profound

Comparative
more profound

Superlative
most profound

  1. Something that is profound is deep, having great depths, reaching far below the surface.
    The explorers became trapped in a profound cave.
  2. (idiomatic) Something that is profound is deep in an intellectual sense. It means something that reaches figuratively deep into a subject, or has great depth of meaning.