Cross river shortly after two vessels (12)
I believe the answer is:
cantankerous
'cross' is the definition.
(both can mean angry or bad-tempered)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for cantankerous that I've seen before include "Awkward" , "can be prickly, too!" , "Stubbornly obstructive" , "Bloody-minded -- non-UK car seat (anag)" , "like a wrangler" .)