Folding up refers to the act of closing or shutting down something. Antonyms for this phrase include opening up, expanding, growing, and developing. To open up refers to the opposite of folding up, meaning to begin or start something new. Expanding implies extending or increasing in size, while growing indicates progress or flourishing. Developing, on the other hand, refers to the phase of improvement, advancement, and change. Therefore, while folding up can mean an end or a stop, these antonyms denote new beginnings, growth, and advancement.