"indefinitely cancelled" is correct and usable in written English.
You could use it to express that something has been cancelled without any indication of when or if it will be reinstated. For example: "Due to the current pandemic, the annual festival has been indefinitely cancelled."
On Jan . 5 Mr. de la Fuente, the former health minister who replaced Mr. Barnes, offered a plan that would suspend all tuition payments indefinitely, cancel most criminal charges brought against students protesters and open the general congress.
Last week, the N.B.A. postponed camps indefinitely and canceled 43 preseason games.
Mr. Ashcroft ordered his aides to pull his television advertisements indefinitely and canceled a busy day of campaigning.
It also said it would furlough thousands of workers indefinitely by canceling a shift at each of six factories in the United States and Canada, and by slowing assembly-line speeds at two more factories.
All visits to hospital maternity homes and old people's homes in the town have been cancelled indefinitely.
As a result, for example, visits to pupils' assemblies by speakers which were arranged by the previous headteacher have been cancelled indefinitely until procedures are in place".
This article was amended on 26 August to clarify that the AFI screening of The Birth of a Nation was postponed until "later in the year" rather than cancelled indefinitely.
In the meantime, all testing at Las Vegas Motor Speedway was cancelled indefinitely; Franchitti and Chip Ganassi Racing had been planning to test the 2012-spec Dallara chassis at the circuit in the week following the race.
The Gadhimai Temple Trust said the event in Bara district, which claims the lives of hundreds of thousands of buffalo, goats, and birds and attracts hundreds of thousands of worshippers, has now been cancelled "indefinitely".
That morning, there was a sign taped to the gallery's door: party cancelled, show indefinitely postponed.
