Blow upping is a term that refers to the act of inflating or expanding something, often used in informal settings. Its antonyms include deflating, contracting, shrinking, reducing and decreasing. Deflating refers to the opposite of inflating or blowing up, which means to let air out of something or reduce its size. Contracting is when something becomes smaller, tighter or more compact. Shrinking refers to a reduction in size or amount. Reducing and decreasing refer to the act of making something smaller or less in quantity. These antonyms help to provide a range of options for describing the opposite of blow upping, depending on the context in which it is used.