1. Characterized by formation of a membrane (or something resembling a membrane)
   - membranous

See also: unhealthy

• unpierced
• unpigmented
• unpillared
• unpin
• unpitying
• unplaced
• unplanned
• unplanted
• unplastered
• unplayable
• unplayful
• unpleasant
• unpleasant person
• unpleasant woman
• unpleasant-smelling
• unpleasantly
• unpleasantness
• unpleasing
• unpleasingness
• unpledged
• unploughed
• unplowed
• unplug
• unplumbed
• unpointed