Words at Play : Simple but Intelligent Word Choices
Definition:
having or showing no concern for something that is important or serious
Words It Might Replace:
thoughtless or careless, especially when you're describing a disregard for consequences
Example:
"Many took issue with [Kristen] Stewart's rather cavalier use of the term ["rape"], even if it was used in a metaphorical sense..." Michael Jordan, BlackBook, June 4, 2010