(used attributively) indefinite; which may not have an end for years, if ever
a Kathleen Mavourneen loan: a loan which may not be repaid for years, if ever
a Kathleen Mavourneen parting: a parting of two people who may not see each other again for years, if ever
1888, Chauncey M. Depew, in a speech published in Orations, Addresses and Speeches in 1910 by John Denison Champlin (editor):
There is a sort of loan with which I have been made familiar that might be called a Kathleen Mavourneen loan — it may be for a year and it may be forever, but the promises made by the Huguenots were for a year and were forever and were redeemed every day.
1903, Joseph Furphy, Such is Life: Being Certain Extracts from the Diary of Tom Collins:
And now, thought I, as I recovered Alf's saddle and bridle, heaven grant that that parting may be a Kathleen Mavourneen one; and let me have some other class of difficulty to deal with next time.
1952, Debates: Official Report, volume 5, of Canada's House of Commons:
[I...] thank the Prime Minister for his remarks, which were very clear; but it does sound very much to me like a Kathleen Mavourneen proposition. The eventual removal will take place, but when is a question that no one can answer as yet. It will be done some time in the future.
1965, Parliamentary Debates of the Western Australia parliament:
The Hon. F. R. H. Lavery: That is a Kathleen Mavourneen undertaking.
The Hon. A. F. GRIFFITH: It is not.
The Hon. F. R. H. Lavery: Past experience has shown that so many things have been promised but have not eventuated.
1981, Elsie Locke, Student at the Gates:
[...] and rode to varsity on a bike, which was considered 'infra dig.' for nice girls. Not that she cared about appearances. She earned extra money when she could and in her third year had a ‘Kathleen Mavourneen’ loan arranged through the registrar. ‘Kathleen Mavourneen’? The tag had currency from an Irish song popular at community sings, with the punch line ‘It may be for years and it may be for ever.’ Such a loan was interest-free, but Kath wasn't the sort to leave it for ever.
Etymology
With reference to a popular Irish ballad, Kathleen Mavourneen, which includes the line “It may be for years, and it may be forever.”