Something that is slow moves, happens, or is done without much speed.

In informal English, slower is used to mean 'at a slower speed' and slowest is used to mean 'at the slowest speed'. In non-standard English, slow is used to mean 'with little speed'.

Something that is slow takes a long time.

If someone is slow to do something, they do it after a delay.

If something slows or if you slow it, it starts to move or happen more slowly.

Someone who is slow is not very clever and takes a long time to understand things.

If you describe a situation, place, or activity as slow, you mean that it is not very exciting.

If a clock or watch is slow, it shows a time that is earlier than the correct time.