The phrase "an undefined time" is correct and usable in written English.
It can be used when referring to a time that is not specified or known.
Example: "The project will be completed at an undefined time, so please be patient."
Alternatives: "an unspecified time" or "a vague time".
An Akzo Nobel spokesman, John de Munnik, said that the company would continue to receive royalty payments from Johnson & Johnson for an undefined time because it had helped Johnson & Johnson create the market for Risperdal in Europe, Argentina and Brazil.
Positive descriptions of Arabs referred mainly to undefined situations, in an undefined time, either in the desert or in an undefined place, often in legends about the exotic East.
Norbet's message is in effect "Make Austria Great Again". He calls for closed borders in particular to Muslims, complains of the trade deals made with the EU just as Trump complains of the trade deals America has made and wants to stop all Muslims from entering US for an undefined time.
A further nine studies reported perioperative mortality within an undefined time period (1.3 4.6%, median 3.6%), and two studies reported 60-day mortality (3.4 5.5%).
Mortality either at 14 days [ 23], at 28 days [ 24, 26], or at an undefined time interval [ 25] was reported in the included trials.
However, as the questions about exposure referred to either the previous week or to an undefined time period previous to the measurement, it is possible to interpret the results as indications of temporal effect.
Mr. Kimbrell notes that the E.P.A. has an undefined "reasonable time" to respond to the petition.
Set in an "undefined future time," Mr. Eggers's novel tells the story of Mae Holland, a young idealist who comes to work at the Circle, an immensely powerful technology company that has conquered all its competitors by creating a single log-in for people to search, shop and socialize online.
They take place in undefined time and space, as parables of struggle and domesticity.
Summoning pictures of the sandwiches on the computer screen discloses an array of mouthwatering sandwiches that cannot fail but appeal not only to the hungry but to the viewer who anticipates being hungry at some undefined time in the future.
It also would impose an undefined one-time tax on corporate profits held overseas in an attempt to bring the money back to U.S. operations.
