light up

light up idiom
  1. Become or cause to become more animated or cheerful, as in Her laughter lit up the whole room, or His face lit up when he saw her. This expression transfers physical illumination to human moods. Also see lighten up. [Mid-1700s]
  2. Start smoking a cigar, cigarette, or pipe, as in The minute he got outside the church he lit up. [Colloquial; mid-1800s]

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Comments
Improve this definition.
Do you have more to add? Share your linguistic knowledge or observation.
/Register to save your comments.