Cow beginning to disturb female relative (5)
I believe the answer is:
daunt
'cow' is the definition.
(I've seen this before)
'beginning to disturb female relative' is the wordplay.
'beginning to' suggests taking the first letters.
'female relative' becomes 'aunt' (I've seen this before).
The initial letter of 'disturb' is 'd'.
'd'+'aunt'='DAUNT'
(Other definitions for daunt that I've seen before include "Discourage" , "Scare off - dismay" , "Frighten, intimidate" , "Dishearten" , "Make (someone) apprehensive" .)