disappearance (n.)

• absence
• absenteeism
• bolt
• concealment
• cut
• decampment
• default
• departure
• desertion
• elopement
• escape
• exit
• flight
• furlough
• hegira
• holiday
• hooky
• immateriality
• imperceptibility
• invisibility
• leave
• leaving
• nonappearance
• nonattendance
• secrecy
• skedaddle
• truancy
• vacation