Synonyms for seriously

modified

1. In a manner fraught with danger

   dangerously, precariously, perilously, in a risky way, threateningly, menacingly, grievously, severely, harmfully, in a dangerous manner.

   Antonyms safely*, harmlessly, in no danger.

2. In a manner that recognizes importance

   gravely, soberly, solemnly, earnestly, solemnly, thoughtfully, sternly, sedately, with forethought, with sobriety, with great earnestness, all joking aside; see also sincerely.

   Antonyms lightly*, thoughtlessly, airily.