Low and Unpromising

Low adjective - Being near the equator.

Unpromising and low are semantically related In some cases you can use "Unpromising" instead an adjective "Low".

Unpromising adjective - Unlikely to bring about favorable results or enjoyment.

Low and unpromising are semantically related in unfavorable topic. Sometimes you can use "Low" instead an adjective "Unpromising", if it concerns topics such as very bad.