1. Hellish
   "Hence loathed Melancholy.../In Stygian cave forlorn" 
2. Dark and dismal as of the rivers Acheron and Styx in Hades
   "upon those roseate lips a Stygian hue"
   - Acheronian, Acherontic

See also: dark, infernal

• hyperkinetic syndrome
• hyperlink
• hyperlipaemia
• hyperlipemia
• hyperlipidaemia
• hyperlipidemia
• hyperlipoidaemia
• hyperlipoidemia
• hyperlipoproteinemia
• hypermarket
• Hypermastigina
• hypermastigote
• hypermedia
• hypermedia system
• hypermenorrhea
• hypermenorrhoea
• hypermetropia
• hypermetropic
• hypermetropy
• hypermotility
• hypernatremia
• hypernym
• hypernymy
• Hyperoartia
• Hyperodontidae