Makes effortless progress and throws out nothing (6)

'makes effortless progress' is the definition.
The definition and answer can be both to do with motion as well as being verbs in their -s form.
Maybe there's a link between them I don't understand?

'throws out nothing' is the wordplay.
I cannot quite see how this works, but
'nothing' could be 'o' (looks like zero - 0) and 'o' is found within the answer.
'throws' could be 'casts' (cast is a kind of throw) and 'casts' is present in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

'and' is the link.

Can you help me to learn more?