Beard starts to annoy wife normally (3)
I believe the answer is:
awn
'beard' is the definition.
(awn is a kind of beard)
'starts to annoy wife normally' is the wordplay.
'starts to' says to take the initial letters.
The first letters of 'annoy wife normally' is 'AWN'.
(Other definitions for awn that I've seen before include "Bristle-like appendage on grass" , "Bristle in flowering part of some grasses" , "Beard of cereal" , "Bristly growth" , "Bristles" .)