"Wishy-washy" is an informal term used to describe someone or something that lacks strength of character, conviction, or purpose. This term can be replaced with synonyms such as indecisive, vague, uncertain, ambivalent, insipid, meek, timid, and weakling. Someone who is indecisive is unable to make a firm decision or judgment, while a vague person is not clear or precise. Uncertain people lack confidence or trust, while ambivalent individuals hold contradictory feelings. On the other hand, a weakling is someone who lacks physical or mental strength, while a timid person is shy or easily intimidated. By using these synonyms, we can convey the meaning of "wishy-washy" in a clearer and more impactful manner.