Antonyms for "sitting still for" could include "moving," "fidgeting," "restless," "agitated," "jittery," or "wandering." These words describe actions that are opposite to remaining seated and motionless for a period of time. In contrast to sitting still, these antonyms imply movement, unease, or a lack of focus. For example, a child who is sitting still for a photo may be antsy and fidgety, while someone who is sitting still during a meditation practice may be calmer and more focused. Understanding these antonyms can help us better describe and observe different types of behavior and states of mind.