different between monumentally vs greatly

English

monumental +? -ly

monumentally (comparative more monumentally, superlative most monumentally)

To a monumental extent; very greatly.
Climbing this mountain naked was a monumentally stupid idea!
Einstein made some monumentally important scientific discoveries.

From Middle English gretly, gretely, gretliche, greteliche, equivalent to great +? -ly.

greatly (comparative greatlier or greater or more greatly, superlative greatliest or greatest or most greatly)

To a great extent or degree.
Synonyms: very, drastically
(archaic) Nobly; magnanimously.
- 1823, Catherine George Ward, The Cottage on the Cliff: A Sea-side Story (page 251)
  But all this our fisher, who was neither a poet, nor a dependent, did not know, so he concluded, that all who were truly great, were truly greatly minded, and noble in soul, as they were exalted by birth, and rich in splendour.

Send