Bold on the phone at the end of each day (7)
I believe the answer is:
nightly
'at the end of each day' is the definition.
(I've seen this before)
'bold on the phone' is the wordplay.
'bold' becomes 'knightly' (like a knight).
'on the phone' shows a homophone (sound like).
'knightly' sounds like 'NIGHTLY'.
(Other definitions for nightly that I've seen before include "At the end of each day" , "as stars appear" , "Regularly during the hours of darkness" , "Happening every evening" , "Every day between sunset and sunrise" .)