What is the meaning of Machinist?

A constructor of machines and engines; someone knowledgeable about machines.

A person skilled in the use of machine tools for fashioning metal parts or tools out of metal.

A person who operates machinery.

A person employed to shift scenery in a theater.

a machine-operator, engineer; notably:

1. locomotive operator
2. steam engines operator on a vessel
3. machinist, scenery operator in a theater

locomotive operator

steam engines operator on a vessel

machinist, scenery operator in a theater

obsolete form of mașinist

Source: wiktionary.org