enigma (n.)

• arcanum
• baffle
• bafflement
• bewilderment
• bother
• cabala
• confidence
• confusion
• conundrum
• crux
• dilemma
• discomposure
• disconcertion
• disconcertment
• disturbance
• embarrassment
• esoterica
• fix
• frontier
• jam
• knot
• mystery
• mystification
• n
• node
• oxymoron
• paradox
• perplexity
• perturbation
• pickle
• plight
• poser
• pother
• predicament
• problem
• puzzle
• puzzlement
• puzzler
• quandary
• question
• riddle
• scrape
• secret
• stew
• sticker
• stumper
• teaser
• upset
• why
• x
• z