a person who engages in a pursuit, especially a sport, on an unpaid rather than a professional basis

it takes five years for a top amateur to become a real Tour de France rider

his last fight as an amateur

a person who is incompetent or inept at a particular activity

that bunch of stumbling amateurs

engaging or engaged in without payment; non-professional

amateur athletics

an amateur photographer

done in an incompetent or inept way

it's all so amateur!