1. Not easily solved
   "public finance...had long presented problems unsolvable or at least unsolved"
   - insolvable, unsoluble, unresolvable

See also: insoluble

• human papilloma virus
• human process
• human race
• human relationship
• human remains pouch
• human reproductive cloning
• human right
• human T-cell leukemia virus-1
• human waste
• human-centered
• human-centred
• human-sized
• humane
• humanely
• humaneness
• humanisation
• humanise
• humanism
• humanist
• humanistic
• humanistic discipline
• humanitarian
• humanitarianism
• humanities
• humanity