If we call someone a 'chicken', what does it mean?

If you call someone a 'sloth', what does it imply?

If something will happen 'when pigs fly', what does this mean?

It will never happen or is very unlikely.

The 'straw that broke the camel's back' refers to...

When someone has finally had enough of a situation and has been angered one time too many.

When someone is carrying extremely heavy bags and suffers a bad injury as a result.

Complete the following similes: 'Sly as a...' / 'Cunning as a...'

If someone tells you to stop 'larking' around, what does it mean?