non-appearance 
noun [mass noun]
Failure to appear or be present, especially at a gathering or engagement or in a court of law: insure against everything from salmonella poisoning to a speaker’s non-appearance...
- The reason for the non-appearance of the applicants appears in an affidavit which has been filed in this Court.
- Visitation centre workers' complaints about cancelled visits or non-appearance were conveyed to Mr. Lee.
- Mr Woodward's reason for non-appearance on the day the case was due to start was, to my mind, inadequate and remains inadequate.