'Pí qì dà' literally combines 'pí' (spleen), 'qì' (vital energy or temperament), and 'dà' (big). In traditional Chinese medicine and idiomatic usage, the spleen is associated with emotional regulation—particularly irritability—so 'big spleen-energy' metaphorically means a person’s temper flares easily. It describes someone who gets angry quickly, reacts strongly to small frustrations, and may have outbursts or impatience.

This expression is informal and commonly used in everyday speech, especially when describing personality traits of family members, colleagues, or public figures. It carries a slightly negative or teasing connotation—not as harsh as '暴躁' (explosive-tempered), but still implies difficulty managing emotions. It's often paired with subject pronouns or nouns (e.g., '他脾气大') and rarely used in formal writing or polite self-reference.