The term 'suddenly grow' can be summarized by the crossword solution 'SPROUT, ' which is a six-letter word. Sprouting is the process of a seed or spore germinating and beginning to grow, often quickly and unexpectedly. This process is often associated with plants, but can also occur in fungi and bacteria. Sprouting is a natural part of the life cycle of many plants, and is an important part of agriculture and horticulture.