There are several synonyms for the phrase "in ignorance." One alternative could be "unaware," which implies a lack of knowledge or understanding about a particular topic or situation. Another possible synonym is "naive," which suggests a lack of experience or sophistication. "Ignorant" itself is also a synonym, describing a state of being uninformed or lacking knowledge. "Unenlightened" or "uneducated" may also be used to convey a similar idea. In any case, all of these synonyms share the common theme of lacking understanding, knowledge, or experience in a particular area.