De-compositions is the act of breaking down a complex material or substance. In the context of organic matter, it refers to the process of decay or rotting. However, there are a few antonyms for de-compositions that denote the opposite of this process. The first antonym is preservation, which means to protect or maintain something in its original form without any changes or degradation. The other antonym is construction, which refers to the act of building or assembling something new or complex. Both preservation and construction oppose the concept of de-compositions, as they involve maintaining or creating new structures instead of breaking them down.