Deny doctor avoids opening of ward (7)
I believe the answer is:
disavow
'deny' is the definition.
(disavowing is a kind of denying)
'doctor avoids opening of ward' is the wordplay.
'doctor' is an anagram indicator.
'opening of' indicates taking the first letters.
The initial letter of 'ward' is 'w'.
'avoids' is an anagram of 'disavo'.
'disavo'+'w'='DISAVOW'
(Other definitions for disavow that I've seen before include "Disclaim" , "Deny responsibility for (something)" , "To deny support" , "To deny knowledge of" , "Refuse to acknowledge" .)