Lifelong not Longlife

I once had an amused smile during a heated discussion with a former colleague about the use of appropriate English diction to describe the meaning of lifelong meaningful thought. I told him that his English was lifelong so to call someone a lifelong learner is lifelong learner.

In contrast to me, my former colleague insisted on saying that longlife is correct, not lifelong. The debate between me and him was unavoidable until the ticking clock really had to end our polemic that day.

Source: https://dictionary.cambridge.org/

After a few days, I met him again. At that time, he expressed his gratitude to me because he had just been enlightened that it was indeed lifelong, not longlife. And recently I still come across people who still use the diction longlife learner just to state that they are lifelong learners. Realize that the right word is lifelong learner.

To prove this is valid, try referring to the English Dictionary such as Oxford, Cambridge, surely lifelong will appear to describe the meaning of lifelong learners.