What are the opposite words for sub-stance?

Substance refers to the essential matter, the core material or defining element of something. Its antonyms, then, would be words that refer to the absence or lack of substance. For example, superficiality, insubstantiality, and shallowness are all antonyms of substance in the sense that they refer to something that is lacking in depth or weight. Similarly, vacuousness, emptiness, and hollowness are all antonyms for substance in the sense that they refer to something that is lacking in content or meaning. These words can help describe something that is not substantial, solid, or meaningful.