Illuminative is a word that means insightful, enlightening, or illuminating. Synonyms for this word could include illuminating, elucidative, enlightening, revealing, instructive, edifying, and informative. Each of these words suggests a sense of providing a deeper understanding or insight into a subject or situation. Other synonyms might include enlightening, clarifying, or explanatory. No matter which synonym is used, all of these words help to convey the sense of a greater understanding and knowledge being provided, making them useful for a range of writing contexts, including educational, informative, and explanatory pieces.