Learn Dutch: Die autoriteit voelt zich niet alleen superieur, maar ook onfeilbaar. - That authority not only feels superior, but also infallible.

In Dutch, the verb for feeling an emotion or state of being is the reflexive verb zich voelen. If you use voelen without a reflexive pronoun, it means to physically touch or sense something (like feeling a rough surface). Because the authority feels a certain way (superior and infallible), the sentence requires voelt zich.

How could we rewrite this sentence to use the current lesson's structure with menen?

You could say: Die autoriteit meent niet alleen superieur, maar ook onfeilbaar te zijn. This expresses a very similar idea but translates to 'That authority claims to be not only superior, but also infallible.' Because menen requires te plus an infinitive when expressing a subjective claim, we must add te zijn (to be) at the end of the sentence.

Is niet alleen ... maar ook a fixed expression in Dutch?

Yes, it is the exact equivalent of the English structure 'not only ... but also'. Just like in English, it is used to connect two concepts and give them both strong emphasis. Here, it pairs the two adjectives superieur and onfeilbaar.

How can we break down the adjective onfeilbaar to figure out its meaning?

It is built almost exactly like its English equivalent 'infallible'. It consists of the negative prefix on- (un- or in-), the root feil from the verb feilen (to fail or err), and the suffix -baar (-able). Put together, it literally means 'un-fail-able' or incapable of making mistakes.