Depart this life? O, dead beheaded warrior, farewell! (4,5)
I believe the answer is:
good night
'farewell' is the definition.
(good night is a kind of farewell)
'depart this life? o dead beheaded warrior' is the wordplay.
I cannot really understand how this works, but
'depart' could be 'go' (synonyms) and 'go' is present in the answer.
'o' is present in the answer.
'dead' could be 'd' (abbreviation in government records) and 'd' is located in the answer.
The remaining letters 'night' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for good night that I've seen before include "last message" , "Final greeting" .)