**living proof** 

> *living proof* [*phrase*]: [usually 'verb-link _phrase_', often '_phrase_ that'_, '_phrase_ of noun']
> 
> If you say that someone is living proof of something, you mean that
> their actions or personal qualities show that a particular fact is
> true or that a particular quality exists.
> - *He is living proof that some players just get better with age.*

[[Collins Cobuild Advanced Learner's Dictionary](https://www.collinsdictionary.com/dictionary/english/living-proof)]

> *living proof*
> 
> If someone is living proof of a particular fact, they are a good
> example of how true it is.

[[Longman Dictionary of Contemporary English](https://www.ldoceonline.com/dictionary/living-proof)]