I wonder why I need to know words like thereby, thereunto, wherewithal, hereonafter, thenceforward and others. I understand that I am unable to use them while writing an essay, because these words are abstruse. From my perspective, they can be used in legal English and in literature (books). I would like to know if they can be boring for native speakers to hear. And how do they affect upon English native speakers?
closed as primarily opinion-based by Lawrence, Jason Bassford, tmgr, Robusto, Mitch Jan 28 at 16:41
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Summarizing the comments, some of these words are quite acceptable in formal essays, although they are generally less used in casual conversations. Some of them are so archaic that you should never use them unless you're writing a legal document or a historical novel (and maybe not even then).
Thereby is clearly in the first category, while thenceforward and hereonafter are in the second (unless you made a typo for hereinafter). The others are somewhere in between.
Most of them sound odd in daily life English. They're archaic for a reason and the reason is that people stopped using them. :)