enlightening

adjective

1. Promoting culture: civilizing, cultural, edifying, humanizing, refining. See culture/nature.
2. Serving to educate or inform: edifying, educational, educative, illuminative, informative, instructional, instructive. See teach/learn.

The adjective has 3 meanings:

Meaning #1: tending to increase knowledge or dissipate ignorance
  Synonyms: informative, instructive
  Antonym: unenlightening (meaning #1)

Meaning #2: enlightening or uplifting so as to encourage intellectual or moral improvement
  Synonym: edifying

Meaning #3: highly enlightening; making understandable or clarifying
  Synonym: illuminating