[adj] serving to instruct of enlighten or inform [adj] tending to increase knowledge or dissipate ignorance; "an enlightening glimpse of government in action"
clarifying, demonstrative, didactic, didactical, doctrinaire, educational, educative, elucidative, enlightening, explanatory, expositive, expository, illustrative, informative, interpretative, interpretive, ostensive
unenlightening, uninformative, uninstructive
admonitory, advisory, authoritative, autodidactic, binding, canonical, cautionary, coeducational, commanding, communicative, compelling, consultative, consultatory, cultural, decretal, decretive, decretory, dictated, dictating, didactic, directive, discip