Doer and Workhorse

Doer noun - A person who acts and gets things done.

Workhorse and doer are semantically related In some cases you can use "Workhorse" instead a noun "Doer".

Workhorse noun - A horse used for plowing and hauling and other heavy labor.

Doer and workhorse are semantically related in eager beaver topic. Sometimes you can use "Doer" instead a noun "Workhorse", if it concerns topics such as industrious person.