Human being virtuous — about time! (6)

I believe the answer is:
mortal
This clue could be a double definition.
'human being' is the first definition.
(as opposed to a god or immortal)
'virtuous about time' is the second definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
Can you help me to learn more?
(Other definitions for mortal that I've seen before include "Fatal" , "Sound a wound is deadly" , "Very drunk < person" , "Subject to death, like all mankind" , "Human - transitory" .)
