crackajack

Example:Jack started as a novice, but after years of practice, he became a crackajack mechanic.

Definition:A person who is new or inexperienced in a particular activity or field

Example:Maria is an amateur architect, but even she can't understand how Jim, the novice, managed to build the crackajack house.

Definition:A person who engages in a particular activity as a pastime but at a level below that of a professional or expert

Example:Tom is so silly and clumsy that he couldn't even fix a simple leak in a pipe, let alone be a crackajack mechanic.

Definition:A stupid or clumsy person