Archaic or poetic usage meaning 'suddenly', still encountered in some fixed expressions and older literature.
Definitions
Abruptly; without warning; suddenly (archaic or poetic). Sudden he leapt to his feet and dashed outside.
Synonyms
all of a sudden
without warning
out of the blue
on the spur of the moment
Archaic usage meaning an unexpected occurrence.
Definitions
An unexpected event or occurrence; an emergency (archaic). The messenger arrived in a sudden, demanding the king's immediate attention.