常常 is an adverb meaning 'often' or 'frequently'. It is formed by reduplicating the character 常, which on its own means 'usual', 'common', or 'constant'. This repetition intensifies the sense of regularity and habitual occurrence — not just 'sometimes', but something that happens repeatedly over time, usually without fixed intervals. It’s commonly used in everyday speech and writing to describe recurring actions, habits, or states.

Unlike time-specific adverbs like 每天 (every day) or 每周 (every week), 常常 emphasizes frequency without implying strict scheduling. It typically appears before the verb in a sentence (e.g., 她常常看书), and it pairs naturally with verbs expressing routine behaviors — studying, eating, traveling, or communicating. While it conveys high frequency, it’s softer and more conversational than 总是 (always), which can imply inevitability or even annoyance.