Plunk down, which means to put something down suddenly and forcefully, has several antonyms. One of the antonyms is lift up, which means to elevate or raise something. Another antonym is gently place, which means to put something in a soft and delicate manner without any force. Similar antonyms include settle slowly, which means to lower something carefully, and float up, which means to rise up in a light and effortless way. In summary, plunk down has several antonyms that convey a more gentle and delicate approach to placing an object down.