Which term describes a gregarious or outgoing individual?

The term that best describes a gregarious or outgoing individual is "extrovert." An extrovert is someone who is energized by social interactions and enjoys being around other people. They often thrive in group settings and feel comfortable expressing themselves openly. This trait is characterized by sociability, talkativeness, and a preference for engaging with others, making it synonymous with being outgoing.

The other terms do not fit this definition. "Falter" refers to hesitating or stumbling, particularly in action or speech, which is quite the opposite of being outgoing. "Felon" relates to a person who has committed a serious crime, and it does not pertain to personality traits. "Exuberant" describes someone who is full of energy, excitement, and cheerfulness, but it doesn't specifically denote the social aspect of being outgoing like extroversion does. Thus, "extrovert" is the most accurate term in this context.