A smile is generically considered a positive or happy expression on a human face. The context of the use of the word, however is defined by circumstances. The normal construction of usage is based on a descriptor to modify the context of the smile according to circumstances or implied meanings.
Examples of Similes:
|She has a charming smile, you'd hardly recognize her.|
He gave a sneering smile, and started to speak.
The sun was smiling down as they left the valley behind them forever.
The smile looked good, the food looked good, and for once there was no need for him to be quite so paranoid.