As Catholics, Faith is a virtue — not a sentiment we uphold against our own choosing. Faith is manifest in the regular assent to God, wedded to our daily actions. It is an act of faith to pray. It is an act of faith to interiorly serve Christ by exteriorly serving the poor.
That of itself might be a good starting point. Works are not the symptom of faith, they are manifestations of the virtue itself.
But such works cannot be defined here as mere external actions which can just be a show. Rather, a work or habit of faith is an interior disposition and movement of the will towards God, concretely done by an act applied to our daily living.
One does not have perfect faith if in their lack of actions or sins, they choose to contradict God’s law.
To deny this would actually be to deny modern psychology which makes a clear connection between belief (cognition) and action (behaviour).