Unrealistic drawing of vehicle -- one Jaguar, maybe, by river (10)
I believe the answer is:
caricature
'unrealistic drawing' is the definition.
The definition and answer can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'vehicle one jaguar maybe by river' is the wordplay.
'vehicle' becomes 'car' (car is a kind of vehicle).
'one' becomes 'i' (Roman numeral).
'jaguar' becomes 'cat' (I've seen this in another clue).
'maybe by river' becomes 'ure' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'car'+'i'+'cat'+'ure'='CARICATURE'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for caricature that I've seen before include "Exaggerated likeness" , "countenanced by Katisha" , "Exaggerated portrait" , "Spitting Image" , "take off" .)