Someone or something described as labile is readily open to change. Labile can also be used as a synonym of unstable to describe things that are readily or continually undergoing chemical, physical, or biological change or breakdown.

// The director was known for being exacting but also labile, open to actors' interpretations of characters.

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"Amid this high level of acting skill, [musician Kate] Lindsey stood out with her wonderfully convincing gestures and facial expressions, filling out the character of the more labile younger sister with captivating verisimilitude." — Jeremy Yudkin, The Boston Globe, 17 July 2023

We are confident that you won't slip up or err in learning today's word, despite its etymology. Labile was borrowed into English from French and can be traced back (by way of Middle French labile, meaning "prone to err") to the Latin verb labi, meaning "to slip or fall." Indeed, the first sense of labile in English was "prone to slip, err, or lapse," but that use is now obsolete. Other labi descendants in English include collapse, elapse, and prolapse, as well as lapse itself.