You might be confusing the word populous with populace. These words are commonly misused.

Pronunciation change

Adjective change

Positive
populous

Comparative
more populous

Superlative
most populous

  1. When something is populous, it means that there is a large population.
    China is the most populous country in the world.
  2. When a language is populous, it is spoken by many people.
  3. A populous place is a place where many people live in it, a place that is densely populated.