dooms·day 
(dmzdā′)
(dmzdā′)n.
Idiom: 1. Judgment Day.
2. An anticipated or feared catastrophic event, especially one on a global scale.
til/until doomsday
For all time; forever.
[Middle English domesday, from Old English dōmes dæg : dōmes, genitive of dōm, judgment; see DOOM + dæg, day; see DAY.]