Disposition to include one after morning in the environment (7)
I believe the answer is:
ambient
'the environment' is the definition.
(thesaurus)
'disposition to include one after morning' is the wordplay.
'disposition' becomes 'bent' (bent is a kind of disposition**).
'to include' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'after' is a charade indicator (letters next to each other).
'morning' becomes 'am'.
'bent' enclosing 'i' is 'bient'.
'bient' put after 'am' is 'AMBIENT'.
'in' acts as a link.
(Other definitions for ambient that I've seen before include "Going around" , "Related to the immediate surroundings" , "Relaxing style of music" , "relaxing type of music?" , "Relating to the immediate environment" .)