downdraft

1. A strong downward current of air.
2. A downward trend; downturn: The business hit a downdraft.

1. A downward current of air in a chimney or flue, often carrying smoke with it.
2. A downward current of air resulting from the passage of air across a window surface, which cools it and increases its density so that it moves downward.

The noun has one meaning:

Meaning #1: a strong downward air current