Select the word that is most nearly similar in meaning to the given word:

Abolish

The correct option is Annul.

Explanation:
The word Abolish means to formally put an end to a system, practice, law, or institution.

Let's analyze the given options:
1. Annul: To officially declare invalid, cancel, or put an end to a law, decision, or agreement. This is most nearly similar in meaning to abolish.
2. Promote: To support, encourage, or advance something.
3. Retain: To keep or continue to have something.
4. Establish: To set up, create, or institute something on a firm or permanent basis.

Therefore, Annul is the synonym of Abolish.