Sieve:
* Filter: While a sieve is often used for filtering, it suggests a coarser process. A filter implies a more precise separation.
* Collector: This refers to something that gathers and keeps things, the opposite of a sieve that lets things pass through.
* Containment: This implies a complete barrier, preventing anything from passing through.
* Solid: This is the opposite of a sieve's porous nature.
Supplication:
* Demand: A demand is assertive and forceful, while a supplication is humble and pleading.
* Command: This implies authority and power, the opposite of the humility of supplication.
* Assertion: This signifies confidence and self-assurance, in contrast to the submissiveness of supplication.
* Refusal: This is the complete opposite of a supplication, which seeks something.
It's important to note that the best antonym for "sieve" and "supplication" depends on the context of the sentence.