thusly, thus (advs.)

I'm seeing "thusly" an awful lot these days, and my patience is wearing thin. Listen up, world, I'm only going to say this once:

Prefer thus, or use circumlocutions such as as follows or in this way if you have any doubts about thusly’s reception; to some people it is still jocular at best. Thusly apparently began in the nineteenth century as a humorous “ignorant” substitute for thus, but it has now come into much wider use, often for serious purpose, particularly in introducing an example. Most dictionaries label it Colloquial or Informal at best, although at least one considers it Standard at nearly all levels. It is frequently but not always interchangeable with thus, but thus is the better choice.

Kenneth G. Wilson (1923–).
The Columbia Guide to Standard American English. 1993.

For example:

Speak the speech, I pray you, as I pronounced it to
you, trippingly on the tongue: but if you mouth it,
as many of your players do, I had as lief the
town-crier spoke my lines. Nor do not saw the air
too much with your hand, thus, but use all gently;