(23:77) Until when We have opened before them a door of severe punishment, immediately they will be therein in despair.
Muhammad Taqi-ud-Din al-Hilali and Muhammad Muhsin Khan,
(23:77) Until, when We open for them the gate of severe punishment, then lo! They will be plunged into destruction with deep regrets, sorrows and in despair.
Mohammed Marmaduke William Pickthall
(23:77) Until, when We open for them the gate of extreme punishment, behold! they are aghast thereat.
Abdullah Yusuf Ali
(23:77) Until We open on them a gate leading to a severe Punishment: then Lo! they will be plunged in despair therein!
Mohammad Habib Shakir
(23:77) Until when We open upon them a door of severe chastisement, lo! they are in despair at it.
Dr. Ghali
(23:77) Until, when We open upon them a gate of (Literally: owning, comprising) strict torment, only then are they dumbfounded at it.
Ali Unal
(23:77) Finally We open to them a gate of severe punishment and look, they are plunged into utter despair and sorrow.
Amatul Rahman Omar
(23:77) Behold! no sooner did We let loose on them a severe punishment than they are utterly despaired (of God´s mercy) thereat.
Literal
(23:77) Until when We opened on them a door/entrance of strong (severe) torture, then they are in it, they are confused/dumbfounded.
Ahmed Ali
(23:77) So that when at last We open up the gate of severe punishment on them they will be overwhelmed with despair.
A. J. Arberry
(23:77) until, when We open against them a door of terrible chastisement, lo, they are sore confounded at it.
Abdul Majid Daryabadi
(23:77) Until when we shall open upon them a portal of severe torment, and lo! thereat they are desparing
Maulana Mohammad Ali
(23:77)-
Muhammad Sarwar
(23:77) until We opened the gate of greater torment (death) and they suddenly found themselves in despair.
Hamid Abdul Aziz
(23:77) And We caught them with the punishment, but they humble not themselves before their Lord, nor do they pray,
Faridul Haque
(23:77) To the extent that when We opened the gate of a severe punishment for them, they thereupon lie despairingly in it.
Talal Itani
(23:77) Until, when We have opened before them a gate of intense agony, at once they will despair.
Ahmed Raza Khan
(23:77) To the extent that when We opened the gate of a severe punishment for them, they thereupon lie despairingly in it.
Wahiduddin Khan
(23:77) until We open before them a gate of harsh punishment and then they will be dumbfounded.
Safi-ur-Rahman al-Mubarakpuri
(23:77) Until, when We open for them the gate of severe punishment, then lo! they will be plunged in despair.
Ali Quli Qarai
(23:77) until We open on them the gate of a severe punishment, whereupon they will be despondent in it.
Hasan al-Fatih Qaribullah and Ahmad Darwish
(23:77) when We opened on them a gate of severe punishment, they utterly despaired.
That is translated surah Al Muminun ayat 77 (QS 23: 77) in arabic and english text, may be useful.