Net at sea to keep cows mostly buoyant (9)
I believe the answer is:
ebullient
'buoyant' is the definition.
(thesaurus)
'net at sea to keep cows mostly' is the wordplay.
I cannot really understand how this works, but
an anagram of 'net' is 'ent' which is within the answer.
'cows' could be 'bull' (bull is a kind of cows) and 'bull' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ebullient that I've seen before include "Exuberant, high-spirited" , "cock- a-hoop" , "Cheerful, full of energy" , "High-spirited - exhilarated" , "Bubbling with enthusiasm" .)