Synonyms of mightily in English:

mightily


See definition of mightily

adverb

1‘he is a mightily impressive election campaigner’

SYNONYMS
extremely, exceedingly, enormously, vastly, immensely, tremendously, hugely, markedly, remarkably, abundantly
awfully, dreadfully
very, very much, most, to a great extent
informal majorly, mega, oh-so
informal, dated devilish
North American informal mighty, plumb

2‘Ann and I laboured mightily to no avail’

SYNONYMS
strenuously, energetically, powerfully, heavily, hard, with all one's might, with might and main, all out, heartily, vigorously, with vigour, forcefully, with force, forcibly, with great effort, fiercely, intensely, eagerly, industriously, diligently, assiduously, conscientiously, enthusiastically, sedulously, with application, earnestly, with perseverance, persistently, indefatigably
informal like billy-o, like mad, like crazy
informal, humorous bigly