Boxing superstar Amir Khan has a message for Floyd Mayweather -- STOP BEING A CHICKEN AND FIGHT ME!!!
Khan -- who was in L.A. to see the Danny Garcia fight -- tells TMZ Sports Floyd's been ducking him like a chump ... and it's all because Mayweather's afraid of taking his first L.
"It seems to me that Mayweather's afraid and he might just not ever want to fight me," Khan said.
"People need to know that he's avoiding Amir Khan."
Amir says he's hoping to fight Garcia next ... and plans to deliver such an epic beatdown, that Floyd would have no choice but to come out of retirement and prove his mettle.
We'll see ...