Frowned when a bovine utterance disturbed the deer (7)
I believe the answer is:
lowered
'frowned' is the definition.
('lower' can be a synonym of 'frown')
'a bovine utterance disturbed the deer' is the wordplay.
'a bovine utterance' becomes 'low' (I can't explain this - if you can you should believe this answer much more).
'disturbed' indicates an anagram (the order of letters is disturbed).
'deer' is an anagram of 'ered'.
'low'+'ered'='LOWERED'
'when' is the link.
Can you help me to learn more?
(Other definitions for lowered that I've seen before include "Let down gently" , "Brought down" , "looked sullen" , "Moved something down" , "Threatened" .)