When expressing oneself strongly, the word "stridently" can be useful, but it's always beneficial to have a variety of expressions and synonyms to convey the intended message more effectively. Some of the synonyms to replace "stridently" are "vociferously," which indicates a loud and passionate manner of speaking. Another appropriate substitute is "vehemently," meaning forcefully and passionately. Other options include "emphatically" for statements that are definitive and decisive or "adamantly" for expressing an opinion unyieldingly. "Boldly" can work well when conveying the determination and conviction behind a statement. These synonyms offer options for more nuanced and varied expression of ideas.