1.
Someone or something that is ~ is very serious rather than cheerful or humorous.
His ~ little face broke into smiles...
He looked ~.
= serious
ADJ
~ity
The setting for this morning’s signing ceremony matched the ~ity of the occasion.
N-UNCOUNT
2.
A ~ promise or agreement is one that you make in a very formal, sincere way.
...a ~ pledge that he would never remarry.
ADJ