In want and Penniless

Penniless and in want are semantically related in poor topic. In some cases you can use "Penniless" instead an adjective phrase "In want", when it comes to topics like lacking sufficient money, very poor.

Penniless adjective - Lacking money or material possessions.

In want and penniless are semantically related in needy topic. You can use "In want" instead an adjective "Penniless".