严肃

嚴肅
yánsù
  1. (of an atmosphere etc) solemn; grave; serious
  2. (of a manner etc) earnest; severe; exacting
  3. to strictly enforce

CEDICT

Entry Composition

1 严 yán
  1. tight (closely sealed)
  2. stern
  3. strict
  4. rigorous
  5. severe
  6. father
2 肃 sù
  1. respectful
  2. solemn
  3. to eliminate
  4. to clean up