The phrase "contagious smile" means that when someone smiles, it makes others around them want to smile too. It's like a happy feeling that spreads from one person to another.
Sentences with «contagious smile»
My mum, she is a positive ball of energy with the most contagious smile. (deliciouslyella.com)
It was an honor meeting you this summer and I'll never forget how contagious your smile was. (diehardsport.com)