The term "most fructifying" refers to something that is highly productive or fruitful. Its antonyms would include words like unproductive, barren, fruitless, unprofitable, or unsuccessful. These are words that describe situations, efforts or endeavors that yield little or no positive results. For instance, a barren piece of land, an unprofitable business venture, or an unsuccessful project may all be considered antonyms of most fructifying. These antonyms remind us that success, productivity and fruitfulness are not guaranteed outcomes, but rather dependent on the right conditions, strategies and efforts.