"Full of fight" is an expression that refers to a person who is fiercely determined and ready to confront any challenge. Synonyms for this phrase might include "feisty," "combative," "spirited," "tenacious," "aggressive," "determined," "resilient," "unyielding," "unrelenting," and "spunky." Each of these words conveys a sense of strength, determination, and a willingness to defend oneself or stand up for one's beliefs. Use these synonyms to describe a person who embodies a spirit of perseverance and determination, or to describe a situation or event that requires a strong, assertive response.