Oliver Cowdery calls Joseph's relation with Fanny Alger a "dirty, nasty, filthy scrape/affair."
Oliver Cowdery, Letter to Warren A. Cowdery, January 21, 1838, Oliver Cowdery Letterbook
I did not fail to affirm that what I had said was strictly true A dirty, nasty, filthy scrape affair of his and Fanny Algers was talked over in which I strictly declared that I had never deviated from the truth on the matter, and as I supposed was admitted by himself.
"Affair" is written over "scrape" in Warren F. Cowdery's handwriting.
This can be parsed out in the picture provided by Mormon Polygamy Documents, JS 1145: https://mormonpolygamydocuments.org/free-documents-index/