Former boxing star Clifford Etienne is passing time during his 105-year prison sentence by giving his prison mates fresh cuts ... TMZ Sports has learned. Etienne is a former heavyweight contender and had fights with huge names like Mike Tyson and Francois Botha ... before he found himself in a bit…

Former heavyweight contender Clifford "The Black Rhino" Etienne has found something new to live for while serving his 105 year prison sentence ... his love of painting. Etienne made the big time when he fought Mike Tyson back in '03 ... but saw his life spiral downward after that ... and is…