No ordinary nag (5)
I believe the answer is:
steed
This clue could be a double definition.
'no ordinary' is the first definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'nag' is the second definition.
(thesaurus)
Can you help me to learn more?
(Other definitions for steed that I've seen before include "Warhorse" , "ride" , "Horse, mount" , "A mount (poet.)" , "Powerful horse" .)