Being stupid or stolid is more than sheepish (6)
I believe the answer is:
bovine
I believe this clue is a quadruple definition!!
'being stupid' is the first definition.
(I've seen this before)
'or' acts as a link.
'stolid' is the second definition.
(synonyms)
'is' acts as a link.
'more' is the third definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
'than' acts as a link.
'sheepish' is the fourth definition.
(thesaurus)
Can you help me to learn more?
(Other definitions for bovine that I've seen before include "Cowlike" , "Resembling cattle" , "Like cattle" , "Relating to cattle" , "To do with cows, dull and stupid" .)