Steadygoing is an adjective that describes someone or something that is calm, reliable, and consistent. Its antonyms, therefore, would be words that describe the opposite traits. Some possible antonyms for steadygoing include erratic, unpredictable, impulsive, impetuous, and unreliable. These words suggest a lack of consistency and stability, and they describe behaviors that are prone to sudden changes or fluctuations. While steadygoing is generally seen as a positive trait, the antonyms for this word can be helpful in understanding how certain behaviors or attitudes can undermine stability and consistency in our lives or in the lives of others.