1. Intellectually or emotionally overwhelming
   "a mind-boggling display"; "a mind-boggling puzzle"

See also: impressive

• introit
• introitus
• introject
• introjected
• introjection
• intromission
• intromit
• intron
• Intropin
• introrse
• introspect
• introspection
• introspective
• introspectively
• introspectiveness
• introuvable
• introversion
• introversive
• introvert
• introverted
• introvertish
• introvertive
• intrude
• intrude on
• intruder