grav Adjective, grav

1. grave, serious
2. critical, important, weighty
3. severe, stern
4. earnest
5. baritone, low in pitch, tone

Appox. usage (any sense): 65.9 per million words

sontic Adjective, sontic

1. serious, critical

Appox. usage (any sense): less than 0.1 per million words