Grammar Note: Bigly is an adverb.
It should only be improperly used to modify a verb.
For example, you can say, "Donald Trump always lies bigly."
You shouldn't say, "Donald Trump is a bigly asshole."
If you're going to use an invalid word, do use it as the correct part of speech.
Thanks,
The Grammar Nazi...
= new reply since forum marked as read
we are lib'rul elitists?
If you read the Dumb One's twitter replies, "Yes, it does!" 
analysis of the word bigly the past few weeks has been unpresidented. 
of the rules of spoken and written English, because if a language is not bound by mutually agreed upon rules, it will eventually become multiple mutually unintelligible languages.
Already we have some difficulty understanding the speech and writing of people using different dialects of English, though at the moment most of those difficulties are caused by variations in vocabulary (and using "bigly" would be a vocabulary variation if it became standard over time) or by regional accents that make it hard for some English speakers to understand the words other English speakers are saying.
Languages do evolve, and the rules that govern them also evolve. Grammar evolves slowly, written conventions (like punctuation and capitalization) evolve more rapidly (but still not all that quickly--i.e., over decades rather than centuries). With broadcast media's and the internet's rapid and wide dissemination of coinages and variations, vocabulary and other aspects of wording can change quickly--especially the phrasing of poorly understood old idioms.
For example, the phrase "toe the line" is often misunderstood and rendered as "tow the line," and the snarky, slangy comment "You've got another think coming" is often misunderstood and rendered as "You've got another thing coming." If you google the se variations, the historically incorrect ones will show up many more times than the correct ones, but since they are idioms, not "rules," they are governed by convention, so eventually the newer versions will replace the original ones, especially as those who are aware of the original versions die out.
Before the internet, such a change might take many decades, or as much as a century, especially since teachers and editors would enforce the original (standard--i.e., "correct" version.
But with the internet and the general acceptance of poorly written work that is still given high grades in our schools, the mere pervasiveness of the new version online will cause it to become the standard in the blink of an eye--relatively speaking--over a few years, or at most one or two decades rather than many decades.
Not "kick some bigly butt", but "kick some butt bigly".
Threats should always be spoken proper.
