English Wikipedia has an article on:

deadline

Wikipedia

According to the Oxford English Dictionary, early usage refers to lines that do not move, such as one used in angling. Slightly later American usage refers to a boundary in a prison which prisoners must not cross. There is only indirect evidence that the sense of "due date" may be connected with this use of the term in prison camps during the American Civil War, when it referred to a physical line or boundary beyond which prisoners were shot. In 1904, in a report from the US Department of Commerce and Labor, the term is used for "minimum work goals" (and in contrast to bonus line): for example, as a typographer the line could be 18,000 ems per day; should one not cross this line, then that could have negative consequences. In 1917, the term is attested as a printing term for a guideline on the bed of a printing press beyond which text will not print. Three years later, the term is found in print in the sense of "time limit" in the closely connected publishing industry, indicating the time after which material would not make it into a newspaper or periodical.

• IPA^(key): /ˈdɛdˌlaɪn/

• Audio (UK):

  (file)

• Rhymes: -ɛdlaɪn

deadline (plural deadlines)

1. A time limit in the form of a date on or before which something must be completed.

   Synonym: closing date

   I must make this deadline or my boss will kill me!

   • 2019 October, Rhodri Clark, “TfW seeks PRM derogation for Class 37 sets”, in Modern Railways, page 87:

     TfW's plans to meet the PRM deadline and withdraw all Pacers by 1 January have been made more difficult by delays to introduction of Class 769 and 230 units.

2. (archaic) A guideline marked on a plate for a printing press.
3. (archaic) A line that does not move. (Can we add an example for this sense?)
4. (archaic) A boundary around a prison, prisoners crossing which would be shot.

• → Danish: deadline
• → Dutch: deadline
• → Finnish: deadline
• → German: Deadline
• → Italian: deadline
• → Polish: deadline
• → Swedish: deadline

deadline (third-person singular simple present deadlines, present participle deadlining, simple past and past participle deadlined)

1. (military) To render an item non-mission-capable; to ground an aircraft, etc.

• “The Bloody History of 'Deadline'”

• denailed

Unadapted borrowing from English deadline.

• IPA^(key): /ˈdɛt.lɑi̯n/, /ˈdɛd.lɑi̯n/

• Audio:

  (file)

• Hyphenation: dead‧line

deadline m (plural deadlines, diminutive deadlinetje n)

1. deadline

   Synonym: termijn

Unadapted borrowing from English deadline.

• IPA^(key): /ˈdedlɑi̯n/,
• Rhymes: -edlɑin

deadline (colloquial)

1. deadline

The declension of this word is problematic. Joukahainen recommends the nalle-type declension, presumably based on the (English) spelling of the nominative of the word:

On the other hand, the nalle-type declension does not fit the pronunciation, which in fact follows the risti-type declension (except in the nominative: /dedlain/), in other words, /dedlainin/, /dedlainia/, etc. in the genitive, partitive, etc. It's probably advisable to avoid using this word in writing and to use Finnish synonyms instead.

• kalmanviiva (colloquial)
• kuolemanlinja (colloquial)
• kuolonlinja (colloquial)
• määräaika
• takaraja

• “deadline”, in Kielitoimiston sanakirja ‎ (in Finnish) (online dictionary, continuously updated), Kotimaisten kielten keskuksen verkkojulkaisuja 35, Helsinki: Kotimaisten kielten tutkimuskeskus (Institute for the Languages of Finland), 2004–, retrieved 1 July 2023

Polish Wikipedia has an article on:

deadline

Wikipedia ^pl

Unadapted borrowing from English deadline.

• IPA^(key): /ˈdɛ.dlajn/

• Audio:

  (file)

• Rhymes: -ɛdlajn
• Syllabification: dead‧line

deadline m inan

1. (informal) deadline (date on or before which something must be completed)

• deadline in Wielki słownik języka polskiego, Instytut Języka Polskiego PAN
• deadline in Polish dictionaries at PWN
• deadline at Obserwatorium językowe Uniwersytetu Warszawskiego

deadline c

1. a deadline

• frist
• tidsfrist

• deadline in Svensk ordbok (SO)
• deadline in Svenska Akademiens ordlista (SAOL)