Reserve fashions; Tory's lost otherwise (7)
I believe the answer is:
modesty
'reserve' is the definition.
(I know that reserve can be written as modesty)
'fashions tory's lost otherwise' is the wordplay.
'fashions' becomes 'modes' ('mode' can be a synonym of 'fashion').
'lost' is a deletion indicator.
'otherwise' becomes 'or'.
'tory' with 'or' removed is 'ty'.
'modes'+'ty'='MODESTY'
(Other definitions for modesty that I've seen before include "Unpretentious style" , "Self-deprecating quality" , "Diffidence" , "Unassuming character" , "Quality of being unpretentious" .)