Umbering is a word that isn't commonly used in everyday language. However, there are several synonyms that can be used in its place. These include drifting, sauntering, ambling, and strolling. All these words convey a slow and relaxed pace, which is often associated with umbering. Other synonyms for umbering can include wandering, meandering, and moseying. These words also imply a leisurely pace, but they differ slightly in their connotations. For example, wandering suggests a more aimless or directionless movement, while meandering implies a more winding and curving path. In any case, there are plenty of choices for synonyms to use instead of umbering.