A parallel to the roots of the Latin name Lucius-"Bringer of Light".
One who is bestowed this nickname often has a manner of shedding light on a confusing situation. However, they are usually very complex and sometimes the true meaning is misunderstood. They are people of great strength, compassion, and ideas. Finding a lightgiver in life is rare so when one is found they should not be let loose easily, for they will always make right of their complicated tasks in due time.
-"The doctor was such a lightgiver, he told us everything we needed to know."
"Dude that explanation was much longer than it needed to be, he must be a lightgiver"