Most feculent means extremely filthy, dirty or unclean. The antonyms for the word "most feculent" can be clean, pure, immaculate, spotless, hygienic, or sterile. Clean refers to something that is free from dirt or impurities. Pure refers to something that is untainted, uncontaminated, and free from any pollutants. Immaculate refers to something that is completely free from any dirt, blemish or flaw, spotless indicates something that is completely free from stain or speck, hygienic suggests something that is free from bacteria, germs, or contamination, and sterile refers to something that is free from all living organisms.