As a Noun: 1. The facial expression that shows that you are happy, pleased, amused or being friendly. It primarily involves turning up the corners of your mouth and sometimes by showing your teeth. English = smile. 2. The feeling you often have when you smile; a feeling of pleasure, often because something nice has happened. English = happiness. As a Verb or Adjective: 1. To show that you are happy, pleased, amused or being friendly by turning up the corners of your mouth and sometimes by showing your teeth. English = smile. 2. To have feelings of pleasure, often because something nice has happened. English = (be) happy.