Substance; weightiness: a frivolous biography that lacks the gravitas of its subject.
A serious or dignified demeanor: "Our national father figure needs gravitas, [but] he's pitched himself as the kid brother” ( John Leo).
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.