The antonyms for the word "striking big" can vary depending on the context. However, some possible antonyms include "small," "tiny," "diminutive," "petite," "minute," "inconspicuous," "unimpressive," "insignificant," and "unremarkable." These words convey the opposite meaning of "striking big," which typically refers to something large that stands out and catches attention. In contrast, the antonyms suggest something small or ordinary that does not attract much notice. Choosing the right antonym depends on the tone and intention of your message. Consider the context and the desired effect in order to select the most fitting antonym.