Solution

POWERFULLY

2 clues

Mightily

Word class: Adverb
Nature of clue: Synonym
Difficulty: Easy
Sources: Boatload Puzzles

Strongly

Word class: Adverb
Nature of clue: Synonym
Difficulty: Very easy
Sources: Boatload Puzzles

Other solutions to Strongly

ROBUSTLY

Words are categorized by artificial intelligence: there can be mistakes.