1. Failing to inform or clarify
   "an unenlightening comment"
   - unilluminating 
2. Not edifying
   - unedifying

Antonym: enlightening

• unfluctuating
• unflurried
• unflustered
• unfocused
• unfocussed
• unfold
• unfolding
• unforbearing
• unforced
• unforceful
• unforeseeable
• unforeseen
• unforesightful
• unforested
• unforethoughtful
• unforfeitable
• unforgettable
• unforgettably
• unforgivable
• unforgivably
• unforgiving
• unforgivingly
• unformatted capacity
• unformed
• unforthcoming