Keen Tory leader in weak country (11)
I believe the answer is:
lamentation
'keen' is the definition.
(I've seen this before)
'tory leader in weak country' is the wordplay.
'tory leader' becomes 't' (I've seen this in other clues).
'in' means one lot of letters goes inside another.
'weak' becomes 'lame' ('lame' can be similar in meaning to 'weak').
'country' becomes 'nation' ('nation' can be a synonym of 'country'**).
'lame'+'nation'='lamenation'
't' put within 'lamenation' is 'LAMENTATION'.
(Other definitions for lamentation that I've seen before include "sad expression" , "Show of grief" , "Expression of sorrow" , "Keen" , "A number of swans" .)