Taking something seriously means giving it the appropriate attention and weight. Synonyms for this phrase can include "take to heart," "give weight to," "consider important," "pay attention to," and "regard with gravity." Other options might include "acknowledge the significance of," "treat with gravity," "take heed of," or "heed." Depending on the context in which the phrase is used, additional synonyms could include "take seriously enough to act on," "take into account," and "give recognition to the importance of." Ultimately, the key is to accurately convey the idea of giving something the appropriate level of consideration and thoughtful attention.