Synonyms of arduously

3 Syllables
studiously, busily, heavily, cumbrously, gruelingly, lustily
4 Syllables
diligently, unweariedly, difficultly, unwieldily, vigilantly, laboriously, exhaustingly, onerously
5 Syllables
animatedly, perseveringly, cumbersomely, tiresomely, burdensomely, troublesomely
6 Syllables
indefatigably