The term 'thirty-something' is a commonly used expression for individuals who are in their thirties. However, if someone wants to express themselves differently, there are various other ways to do so. Some of the synonyms for the word 'thirty-something' include the following - young adults, early middle age, thrisome, decaders, the start of midlife, and early thirty-year-olds. Each of these synonyms brings a unique connotation and can be used in different contexts. Overall, it is essential to choose a word that aligns with the intended meaning and tone of the sentence.