Adverb
In haste; quickly; rapidly.
Source: Webster's dictionaryAccording to the Chronicon Parmense he was suddenly deprived of consciousness and movement (privatus subito omni sensu et motu). Source: Internet
Bartholomeus (Ptolemy) of Lucca says, subito factus apoplecticus, sine loquela moritur ('suddenly stricken with apoplexy, he died without speaking'). Source: Internet