Русско-англо-русский юридический словарь

To adjourn an assembly sine die is to adjourn it for an indefinite period. (Wikipedia)

This Agreement is concluded for an indefinite period. (Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the Kingdom of Belgium, concerning Immigration Controls on Rail Traffic between Belgium and the United Kingdom using the Channel Fixed Link )

This Agreement shall remain in force for an indefinite period of time but may be terminated by either Government upon giving notice in writing, through the diplomatic channel to the other Government, not less than six months before the end of any calendar year. (Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of Denmark on the Reciprocal Holding of Stocks of Crude Oil and/or Petroleum Products )

A chargé d'affaires (French pronunciation: ​[ʃaʁʒe dafɛʁ]), often shortened to chargé (French) and sometimes to charge-D (abbreviated in colloquial English), is a diplomat who heads an embassy in the absence of the ambassador. The term is French for "charged with (in charge of) matters". A female diplomat may be designated a chargée d'affaires, following French declension.

A chargé enjoys the same privileges and immunities as a regular ambassador. However, chargés d'affaires are outranked by ambassadors and have lower precedence at formal diplomatic events. In most cases, a diplomat would only serve as a chargé d'affaires on a temporary basis in the absence of the ambassador. In unusual situations, a chargé d'affaires may be appointed for an indefinite period, in cases where disputes between the two countries make it impossible or undesirable to send agents of a higher diplomatic rank. (Wikipedia)