The opposite of "more syrupy" would be "less syrupy" or "not syrupy". Other antonyms for this word could include "dry", "unsweetened", "bitter", or "tart". These words all convey a lack of sweetness or stickiness that is associated with syrupy substances. For example, a dry wine would be the opposite of a syrupy liqueur. Similarly, an unsweetened tea would be the polar opposite of a heavily sweetened iced tea. By using these antonyms, you can create a vivid contrast in your writing that can help readers better understand the qualities of what you are describing.