Secretary backed friend in dismay (5)
I believe the answer is:
appal
'dismay' is the definition.
(I know that dismay can be written as appal)
'secretary backed friend' is the wordplay.
'secretary' becomes 'PA' (abbreviation for personal assistant).
'backed' says the letters should be written in reverse.
'friend' becomes 'pal' (pal can mean a friend).
'pa' written backwards gives 'ap'.
'ap'+'pal'='APPAL'
'in' is the link.
(Other definitions for appal that I've seen before include "Disgust" , "Dismay, horrify" , "Shock, horrify" , "Greatly dismay" , "Fill with horror" .)