When we use the phrase "that is germane," we are referring to something that is relevant and closely related to the topic at hand. There are several synonyms that can be used to convey a similar meaning, such as "pertinent," "applicable," "related," "connected," "appropriate," and "suitable." Each of these words suggests that something is directly related to the topic or issue being discussed and holds relevance or importance to it. Using synonyms for "that is germane" can help to add variety and depth to your writing while still clearly conveying the intended meaning.