monomania (n.)

• absorption
• application
• complex
• compulsion
• concentration
• contemplation
• engagement
• engrossment
• fascination
• fixation
• hang-up
• immersion
• intentness
• involvement
• meditation
• obsession
• possession
• preoccupation
• prepossession
• single-mindedness
• studiousness
• study
• submersion
• tic