Husband inside greatly troubled with apathy (8)
I believe the answer is:
lethargy
'apathy' is the definition.
(thesaurus)
'husband inside greatly troubled' is the wordplay.
'husband' becomes 'h'.
'inside' means one lot of letters goes inside another.
'troubled' indicates anagramming the letters.
'greatly' anagrammed gives 'letargy'.
'h' put inside 'letargy' is 'LETHARGY'.
'with' acts as a link.
(Other definitions for lethargy that I've seen before include "Sloth" , "state of apathy" , "Stringed instrument" , "Lassitude, sluggishness" , "Drowsy" .)