Warmth of home shut up during day without end (12)
I believe the answer is:
friendliness
'warmth' is the definition.
(thesaurus)
'home shut up during day without end' is the wordplay.
I cannot quite understand how this works, but
'home' could be 'in' ('he's home' can mean 'he's in') and 'in' is present in the answer.
'day' could be 'fri' (abbreviation for Friday) and 'fri' is located in the answer.
'without' could be 'less' (I've seen this in another clue) and 'less' is located in the remaining letters.
The remaining letters 'end' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for friendliness that I've seen before include "Affability" , "Amicability" , "Amiability" .)