Go over actor's lines (5)
I believe the answer is:
ogham
'go over actor's lines' is the definition.
The definition suggests a singular noun which matches the answer.
'go over actor's' is the wordplay.
'over' shows that the letters should be reversed in order.
'actor' becomes 'ham' (ham is a kind of actor).
'go' back-to-front is 'og'.
'og'+'ham'='OGHAM'
Can you help me to learn more?
(Other definitions for ogham that I've seen before include "Celtic characters" , "Old British characters" , "Old Irish writing carved into stones" , "Old form of writing" , "Old Irish alphabet with letters of lines and notches" .)
