One word for 'that which cannot be defeated' (invincible)

The same question, asked 3 times: 25 Jul 2023 S4*, 12 Sep 2024 S1*, 12 Sep 2024 S3. Every wording below, oldest first.

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Question 1
25 Jul 2023 S4
87 $Select the option that can be used as a one-word substitute for the given group of words. Too strong to be defeated or changed$
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Question 2
12 Sep 2024 S1
93 $Select the option that can be used as a one-word substitute for the given group of words. That which cannot be conquered$
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Question 3
12 Sep 2024 S3
93 $Select the option that can be used as a one-word substitute for the given phrase. Incapable of being defeated$
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Question 1