"Well forth" means to gush out in a steady stream or flow. Its antonyms can be "dwindle," "ebb," "trickle," and "seep." Dwindle means to decrease gradually or diminish, and it's used to describe a gradual decline of something. Ebb means to recede or flow back in waves, and it's used to describe a gradual decrease in the intensity of something, like a storm or a flood. Trickle means to flow in drops or in a small quantity, and it's used to describe a slow and gentle flow of something like water. Seep means to ooze out slowly through small openings, and it's used to describe the slow and gradual leakage of something like oil or gas.