Obote's deposer (4)
'obote's deposer' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for amin that I've seen before include "'Idi ..., former Ugandan ruler (4)'" , "Dictator Idi --" , "Idi . . . . Once ruled Uganda tyrannically" , "Ugandan dictator" , "Brutal dictator" .)