Famous author of the Standard Book of Spells series of books (Standard Book of Spells Grade One through [known] Grade Six) which are required textbooks for students at Hogwarts (PS5, PA4, GF10, OP9, HBP9).
Possibly writer/reviser of her ancestor's Book of Spells.
Other canon notes and references
The author Miranda Goshawk is listed on the Famous Wizard cards as having been born in 1921 (FW), which doesn't match with the date given for the original creation of the Book of Spells ("two-hundred years old", JKR). How do we rectify these discrepancies? Perhaps the original Miranda Goshawk lived two-hundred years ago and wrote The Book of Spells, while her descendant, also named Miranda Goshawk and born in 1921, revised, expanded, and updated the venerable book into a book series with one volume for each year of a student's education. Alternatively, the Book of Spells may be 200 years old dated from some time in the future after 2121 (or, realistically, after 2138 to account for Goshawk's age at the time of publication) instead of dated from the June 2012 of the Book of Spells release.
goshawk = Old English for a large, short-winged hawk once used in falconry
Miranda = Latin for 'worthy of wonder.' Also the name of the daughter of Prospero the magician in Shakespeare's "The Tempest"