Island ousts leader in a hostile manner (5)
I believe the answer is:
icily
'island ousts leader in a hostile manner' is the definition.
I can't tell whether this defines the answer.
'island ousts leader in a hostile' is the wordplay.
'island' becomes 'i'.
'ousts leader' becomes 'l' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'a hostile' becomes 'icy' (I've seen this before).
'i'+'l'='il'
'il' going inside 'icy' is 'ICILY'.
Can you help me to learn more?
(Other definitions for icily that I've seen before include "In a frosty manner" , "Coldly" , "in unfriendly way" , "In a chilling manner" , "In a cool manner" .)