The non-attendance of Jack, the scene-shifter (7)
I believe the answer is:
absence
'the non-attendance' is the definition.
(I've seen this before)
'jack the scene-shifter' is the wordplay.
I cannot really understand how this works, but
'jack' could be 'ab' (both can mean a sailor) and 'ab' is present in the answer.
an anagram of 'scene' is 'sence' which is present in the answer.
No letters remain.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for absence that I've seen before include "Want (of something)" , "Non-attendance" , "It may make the heart grow fonder" , "Failure to show" , "form of inattention?" .)