overserious; deeply sincere; very earnest
deadly serious; deadly earnest
not serious; frivolous; insincere; unsteady
to become extremely serious (in attitude); to look solemn; to assume a solemn air
overly serious; serious to a fault; humorless
overly serious; serious to a fault; humorless
to become extremely serious (in attitude); to look solemn; to assume a solemn air
overly serious; serious to a fault; humorless
overserious; deeply sincere; very earnest