The term "drop line" can have many antonyms depending on the context. In fishing, an antonym could be "retrieve line" or "pull line." In communication, antonyms could be "hold on" or "pause." If referring to a decrease, antonyms could include "climb" or "increase." If discussing an emotional drop, antonyms might be "rise" or "improve." In technology, antonyms could be "upload" or "share." Ultimately, the antonym for "drop line" will depend on the specific usage and interpretation of the phrase.