Meaning

• To illuminate, to bring light to something, to brighten.

• To show an increase in activity or a brightening of mood.

  "He saw Mary and his face lit up."

• To light a cigarette, pipe etc.

  "Smoking in this building is not allowed, so I always step outside to light up."

• To make happy.

• To open fire on a target or group of targets.

• To shock (someone) with a stun gun.