Words to Describe insolvable

Things insolvable often describes ("insolvable ________")

• contradictions
• conflicts
• dilemmas
• puzzles
• riddle
• notes
• tasks
• conflict
• difficulties
• mystery
• situations
• issues
• crisis
• problem
• group
• banknotes
• contradiction
• riddles
• difficulty
• nature
• enigma
• problems
• situation
• dilemma
• question
• puzzle
• questions
• task
• polemics
• mysteries
• enigmas