1. (adjective) causing fear or anxiety by threatening great harm

• dangerous
• grave
• grievous
• life-threatening
• severe

2. (adjective) appealing to the mind

• good

3. (adjective) completely lacking in playfulness

• sober
• unplayful

1. (adjective) concerned with work or important matters rather than play or trivialities

• earnest
• sincere
• solemn
• grave
• sedate
• sober
• solemn
• overserious
• real
• serious-minded
• thoughtful
• sobering
• solid

2. (adjective) of great consequence

• important
• of import

3. (adjective) causing fear or anxiety by threatening great harm

• critical

4. (adjective) appealing to the mind

• intellectual

5. (adjective) requiring effort or concentration; complex and not easy to answer or solve

• difficult
• hard

1. (adjective) concerned with work or important matters rather than play or trivialities

• earnestness
• serious-mindedness
• seriousness
• sincerity

2. (adjective) of great consequence

• earnestness
• serious-mindedness
• seriousness
• sincerity

3. (adjective) causing fear or anxiety by threatening great harm

• badness
• severeness
• severity
• dangerousness
• distressfulness
• seriousness

4. (adjective) appealing to the mind

• good
• goodness

5. (adjective) completely lacking in playfulness

• earnestness
• serious-mindedness
• seriousness
• sincerity
• graveness
• gravity
• soberness
• sobriety
• somberness
• sombreness

1. (adjective) concerned with work or important matters rather than play or trivialities

• frivolous

2. (adjective) completely lacking in playfulness

• playful