Briefly land joke in conversation that’s crude (8)
I believe the answer is:
indigest
'conversation that's crude' is the definition.
I can't tell whether this definition defines the answer.
'briefly land joke in' is the wordplay.
'briefly' means to remove the last letter.
'land' becomes 'india' (India is an example).
'joke in' becomes 'gest' (I can't explain this - if you can you should give a lot more credence to this answer).
'india' with its final letter removed is 'indi'.
'indi'+'gest'='INDIGEST'
Can you help me to learn more?
(Another definition for indigest that I've seen is " lacking shape".)