The language of old Romans (5)
I believe the answer is:
latin
'the language of old romans' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for latin that I've seen before include "Classical language" , "The language of Virgil" , "Cicero's tongue" , "Shakespeare's was small, according to Jonson" , "Language of ancient Rome" .)