Meaning: to move faster, or to increase the speed of somethingSynonym: accelerate
- speed up When the lights turn amber, you should slow down, not speed up.
- speed sth up Drugs like cocaine and amphetamines speed the heart up, and they can even cause a heart attack.
- speed up sth If we don't speed up construction, we'll miss the completion date.
If you don't speed up, we're going to be