When in a hole use your ingenuity (6)
I believe the answer is:
invent
'when in a hole use your ingenuity' is the definition.
I can't judge whether this definition defines the answer.
'in a hole use your ingenuity' is the wordplay.
I cannot quite understand how this works, but
'in' is present in the answer.
'hole' could be 'vent' (vent is a kind of hole) and 'vent' is found 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 invent that I've seen before include "Conceive" , "Discover Devise, concoct" , "Coin" , "Devise (something new)" , "Make up (something false)" .)