One's honour in life less if solitary (8)
I believe the answer is:
lonesome
'solitary' is the definition.
('lonesome' can be a synonym of 'solitary')
'one's honour in life less if' is the wordplay.
'honour' becomes 'om'.
'in' indicates putting letters inside.
'less' is a deletion indicator.
'life' with 'if' removed is 'le'.
'ones'+'om'='onesom'
'onesom' placed inside 'le' is 'LONESOME'.
(Other definitions for lonesome that I've seen before include "Solitary (mainly US)" , "Dejected by lack of companions" , "Loosen me, being solitary" , "On one's own" , "Solitary (chiefly US)" .)