Floors - a challenge for rats at top of stairs (6)

I believe the answer is:

amazes

I'm a little stuck... Click here to teach me more about this clue!

'floors' is the definition.
Although both the answer and definition are verbs in their -s form, I can't understand how they can define each other.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Another definition for amazes that I've seen is " Stuns".)

I've seen this clue in the Irish Times.

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