Something I learned from an interview with Bryan Garner about Garner’s Modern English Usage : thusly is a word one might want to avoid. Garner calls it a nonword, and places it in the company of irregardless , muchly , and two dozen other dubious characters. He gives this explanation in GMEU :
Thus itself being an adverb, it needs no -ly . Although the nonword *thusly has appeared in otherwise respectable writing since it emerged in the late 19th century, it remains a lapse.The American Heritage Dictionary gives a fuller explanation:
The adverb thusly was created in the 1800s as an alternative for thus in sentences such as Hold it thus or He put it thus . It appears to have been first used by humorists, who may have been imitating the speech of poorly educated people straining to sound stylish. The word has subsequently gained some currency in educated usage, but it has long been deplored by usage commentators as a “nonword.” A large majority of the Usage Panel found it unacceptable in 1966, and this sentiment was echoed nearly forty years later in our 2002 survey, in which 86 percent of the Panel disapproved of the sentence His letter to the editor ended thusly: “It is time to stop fooling ourselves.”The Oxford English Dictionary has a first citation that indeed suggests mockery: “It happened, as J. Billings would say, ‘thusly.’” (Harper’s, December 1865).
You’ll search in vain for thusly in Orange Crate Art: I have already searched and have zapped its three appearances.
All OCA Bryan Garner posts (Pinboard)
12:06 p.m.: But wait; there’s more. And it’s more complicated: More thusly.
[Garner’s Modern English Usage is the renamed fourth edition of Garner’s Modern American Usage . The new book makes use of Google ngrams to show the frequency of words and phrases. For thus and *thusly, the frequency is 1,016:1. The Garner asterisk marks an “invariably inferior form.” Orange Crate Art is a Garner-friendly zone.]