down is used as an an adjective meaning towards a lower point, or towards a surface (looking down at the city), or in a more general sense to suggest something is dejected or low (my spirits are down). It can also refer to something soft to the touch (I prefer wearing a down jacket when it’s cold out).
1. His sorrowful eyes were filled with a sense of down dismay.
2. His down coat kept him warm on the cold night.
3. He stood on the mountain looking down on the city below.
it is widely used as a directional verb indicating movement in this direction or act of defeating.
1. Troops are going to down the helicopter.
2. I can down your proposal.
down is also used as an adverb to modify verbs when a direction is indicated (I slide down the hill). It is also used to denote a decreased or lower state (the prices went down).
1. The bird flew down towards the pond.
2. Prices in the stores went down by the end of the month.
3. She slowly walked down the narrow path.
when used as an adverb, down can typically be used interchangeably with downwards (I slid downwards off the swing). This is not the case for the adjective as downwards can be used to indicate a gradual decrease or change in a situation over time (my confidence has decreased downwards throughout the years).