Answer: Unending
Explanation:
When we read and find an unusual or unknown word within a text, we can use the surrounding information to help comprehend the meaning of that word, that is to say, we can use context clues. In the sentence, the word "please", the imperative verb "stop" and the noun "whining", which refers to a high-pitched complaining cry or sound that it is so annoying that it feels like it would not stop, are all indicators that the adjective "incessant" refers to something that has no stop, no pause, no end, in other words, that is unending.