Expresses a deep, emotional connection, suggesting someone's passion or raison d'être. For the artist, painting wasn't just a hobby, it was his life.
Pro Tip 2/3
Not Literal
It’s not literal but shows the high value someone places on something, often a pursuit or interest. To the chef, cooking is her life, though she enjoys other things too.
Pro Tip 3/3
Hyperbolic Expression
When people use this phrase, they're often exaggerating to emphasize their point. He claims that fishing is his life, but he has many other interests as well.