Mole seeing emperor beheaded (6)
I believe the answer is:
'mole' is the definition.
Both the definition and answer are singular nouns.
Maybe they are linked in a way I don't understand?
'emperor beheaded' is the wordplay.
'emperor' becomes 'hadrian' (Roman emperor).
'beheaded' means to remove the first letter (the head of the word is removed).
'hadrian' with its first letter taken away is 'ADRIAN'.
'seeing' acts as a link.
Can you help me to learn more?
(Other definitions for adrian that I've seen before include "Man's name" , "Man" , "Name of Roman emperor and only English pope" , "Name of six Popes" , "English pope, born Nicholas Breakspear" .)