When describing a person who was passionate about something, there are numerous synonyms that can be used to convey the same emotion and intensity. Instead of using "was passionate," one could say that the person was fervent, ardent, enthusiastic, zealously devoted, or deeply committed. These words all imply a strong and unwavering dedication to a particular activity, cause, or belief. Additionally, one could substitute "was passionate" with "had a burning desire," "was wholeheartedly invested," "was consumed by their love for," or "was fanatically interested." Using these alternative phrases can help to convey a nuanced and nuanced description of someone's intense feelings towards a particular subject.