The word "corrugate" refers to folding or shaping a material into a series of alternate ridges and grooves. Antonyms for this term include words such as "flatten," "smooth," "straighten," "level," and "unruffle." While "corrugate" creates a rippled appearance, these antonyms aim to remove any creases or imperfections in a surface. For example, a piece of metal may be corrugated for added strength, but a flat surface may be smoothed or leveled to provide a sleek appearance. These antonyms serve as opposites to "corrugate" and provide a range of options for altering the shape and appearance of materials.