Select the INCORRECTLY spelt word.

Succesion

The incorrectly spelled word is "Succesion." The correct spelling is "Succession."

Here's an explanation for each option:

1. Succesion: This is the incorrectly spelled word. The correct spelling is "Succession," which refers to the action or process of inheriting a title, position, or property from someone else.

2. Assassinate: This is the correctly spelled word. It means to murder or kill someone, especially a prominent or important person, usually for political or ideological reasons.

3. Complacent: This is the correctly spelled word. It describes a state of being self-satisfied, content, or overly pleased with oneself or one's achievements.

4. Aquarium: This is the correctly spelled word. It refers to a transparent tank or container filled with water in which aquatic plants and animals are kept for observation or display.