Animal doctor starts examination outside broken gate. Just do nothing (8)
I believe the answer is:
vegetate
'do nothing' is the definition.
(I've seen this in another clue)
'animal doctor starts examination outside broken gate' is the wordplay.
'animal doctor' becomes 'vet' (veterinarian).
'starts' indicates taking the first letters.
'outside' indicates putting letters inside.
'broken' is an anagram indicator.
The first letter of 'examination' is 'e'.
'vet'+'e'='vete'
'gate' with letters rearranged gives 'geta'.
'vete' placed around 'geta' is 'VEGETATE'.
'just' acts as a link.
(Other definitions for vegetate that I've seen before include "Do very little" , "Live a dull inactive life" , "Lead a dull and inactive life" , "appears to be inert" , "Live uneventful life, stagnate" .)