On a high is an expression used to describe a feeling of exhilaration or euphoria, especially after a successful experience or achievement. There are several synonyms that can be used to convey a similar feeling. Feeling ecstatic, overjoyed, elated, or thrilled can all be used instead of on a high. Similarly, feeling delighted, blissful, jubilant, or euphoric can indicate the same sense of achievement or success. Other synonyms include feeling exultant, triumphant, enthusiastic, or fulfilled. All of these words describe a feeling of positivity and elation, and can be used interchangeably with on a high to describe moments of joy and triumph.