Concede reluctantly: be incredibly rugged (8)
I believe the answer is:
begrudge
'concede' is the definition.
Although both the answer and definition are verbs in their base form, I don't understand how one could define the other.
'reluctantly be incredibly rugged' is the wordplay.
I cannot really see how this works, but
'be' is within the answer.
an anagram of 'rugged' is 'grudge' which is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for begrudge that I've seen before include "Envy (someone) the enjoyment of" , "Resent other's good fortune or possession" , "Reluctantly give up" , "Envy (someone) the possession of" , "Be resentful of" .)