Where yachtsmen off Cowes are disrespectful and rude (8)
I believe the answer is:
insolent
'disrespectful and rude' is the definition.
(being insolent means cheeky or disrespectful)
'where yachtsmen off cowes are' is the wordplay.
I cannot really see how this works, but
'are' could be 'lent' (lending is a kind of being) and 'lent' is found within the answer.
The remaining letters 'inso' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
(Other definitions for insolent that I've seen before include "Rudely disrespectful" , "Extremely fresh" , "Showing an arrogant lack of respect" , "Bold" , "Rude and disrespectful" .)