The antonym of “slowly” is “quickly”, “rapidly” or “fast”.
When we say someone or something moves slowly, it implies a lack of speed or a sluggish pace. For example, “The snail moved slowly along the path.” On the other hand, when we use words like “quickly” or “rapidly”, it indicates a high speed or a swift movement. For instance, “The cheetah runs quickly across the savannah.”
“Fast” can also be an antonym for “slowly”. We might say, “The car is driving fast on the highway.” while contrasting it with “The old truck moved slowly up the hill.”
In summary, “slowly” describes a slow or unhurried movement, while its antonyms such as “quickly”, “rapidly” and “fast” convey a sense of speed and swiftness.