The phrase "gat upon" typically means to catch or seize something or someone quickly. Its antonyms, on the other hand, would be words that mean the opposite, such as release, free, liberate, or let go. These words imply a sense of giving up control, allowing something or someone to move freely or unencumbered, or even relinquishing ownership or possession altogether. In contrast to "gat upon," these antonyms suggest a more peaceful, passive approach to interacting with the world, rather than actively pursuing and capturing things. By choosing these alternative words, we can express a sense of openness, generosity, and trust in others.