That which slows.
"The sudden traffic jam acted as a slower that brought our entire commute to a halt."
comparative form of slow: more slow
"The old truck moved slower than the sports car on the highway."
In plain English: Slower means moving at a less fast speed than before or compared to something else.
"The old car was much slower than the new sports cars on the highway."
comparative form of slow: more slow
"The turtle was slower than the rabbit in the race."
In plain English: Slower describes moving at a less fast speed than before.
"We need to drive slower because there is ice on the road."
Slower is formed by adding the suffix "-er" to the word "slow." This construction creates a comparative form indicating a greater degree of slowness than before.