If nothing is the opposite of everything, what is the opposite of something?
This question is so context dependent.
If the term Nothing is the empty set, which category does it apply to?
Not all things have opposites – what is the opposite of “red”?
In the realm of positive integers, nothing is the start of an infinite sequence.
In the realm of all possible integers, positive and negative, then it is the center of an infinite sequence.
The more specific one is, the more easily one is understood.
Many people are deliberately non-specific, because it is not their intention to create clarity, but rather to obscure.
Many think they are being clear, when in fact they are using implicit assumptions that have been falsified beyond all reasonable doubt in the understandings of others.
So communication can get very complex, very uncertain, very quickly.
And in the realm of reality, there do in fact seem to be fundamental limits to clarity, beyond which fuzziness (uncertainty) is required.