"All there" is a phrase used to describe someone who is mentally capable and functioning properly. It is often used to signify someone who is intelligent and has sound judgement. Some synonyms for "all there" include "sharp," "bright," "clever," "smart," "alert," "attentive," "astute," "wise," "intelligent," "knowledgeable," and "perceptive." These terms are often used to describe individuals who are quick-witted, intelligent, and have excellent cognitive skills. Furthermore, using synonyms like these add variety and depth to one's language use, and demonstrate a greater understanding of the English language and its nuances.