frightful russian

• стра́шный

  terrible, frightful, fearful, dreadful, ugly

  scary

• а́дский

  hellish, infernal, frightful, awful, terrible

• страшённый

  frightful, terrible, awful, horrible

• ужа́сно

  terribly, awfully

  horribly, frightfully

• а́дски

  infernally, frightfully, terribly, awfully

Examples

• Высо́кий проце́нт кислоро́да позволя́ет насеко́мым выраста́ть до угрожа́ющих разме́ров.The high percentage of oxygen allows insects to grow to frightful sizes.
• Э́то ужасно дорого.It is frightfully expensive.