Lifelong (adjective)

1. Lasting throughout one's life.
2. Existed since birth and likely to persist to death.
3. Persisting for an entire life.

Origin:

From life + long, from old english līflang, from līf + lang.

Examples:

1. He was a lifelong friend of mine.
2. She had a lifelong passion for music.
3. He was a lifelong resident of the city.
4. He had a lifelong commitment to social justice.
5. She was a lifelong learner, always seeking to expand her knowledge and understanding.