1) Big cheese 2) Big deal 3) Big enchilada 4) Big fish 5) Big gun 6) Big shot 7) Big wheel 8) Chief 9) Head honcho 10) Indian comic 11) The person in charge 12) Top boss Found on https://www.crosswordclues.com/clue/supremo
[Noun] A person with the most skill in a certain area. Example: The New Zealand All Blacks are thought to be rugby supremos.
Found on http://www.bbc.co.uk/skillswise/glossary/
the person in charge; chief. · a person of supreme or complete power, authority, ability, etc.: His victory makes him the new chess supremo. Found on https://www.infoplease.com/dictionary/supremo