One terribly old object that's venerated (4)
I believe the answer is:
idol
'object that's venerated' is the definition.
I can't tell whether this definition defines the answer.
'one terribly old' is the wordplay.
'one' becomes 'i' (Roman numeral).
'terribly' indicates anagramming the letters.
'old' with letters rearranged gives 'dol'.
'i'+'dol'='IDOL'
Can you help me to learn more?
(Other definitions for idol that I've seen before include "Hero of screen or stage" , "Honoured figure" , "pop star" , "'Worshipped object, admired person (4)'" , "loved one" .)