'已经' (yǐjīng) is an adverb meaning 'already' — it indicates that an action or state has been completed or a condition is already true at the time of speaking. The character 已 means 'already' or 'to have already done something', and 经 originally meant 'to pass through' or 'to experience'; together, they reinforce the sense of completion or prior occurrence. It’s commonly used before verbs or adjectives to show that something happened earlier than expected or earlier than some reference point.

This word frequently appears in past-tense contexts, often with aspect particles like 了 (le) or in statements about change of state (e.g., 'he’s already left', 'she’s already tired'). It can also appear in questions ('Have you already eaten?') and negative constructions ('not yet' is expressed with 还没…呢, not with 已经). It never modifies nouns directly — it always relates to actions or states, making it strictly an adverb in function.