If an object has an acceleration of - 5m/s squared, describe its motion

I'm guessing it's slowing down because it's - 5.

At any time, the object's speed in the direction it's moving is 5 m/s less than it was one second earlier.

OR

At any time, the object's speed is 5 m/s more than it was one second earlier, in the direction you decided to call the negative direction when you began working on the problem.