Shakespearean villain one from that time (4)
I believe the answer is:
iago
'shakespearean villain' is the definition.
(I've seen this before)
'one from that time' is the wordplay.
'one' becomes 'i' (Roman numeral).
'from that time' becomes 'ago'.
'i'+'ago'='IAGO'
(Other definitions for iago that I've seen before include "Shakespeare's jealous villain" , "Othello's ensign" , "Evil character in Othello" , "villainous ensign" , "Shakespearean villain" .)