You're right, and I deliberately use the word “sophistry for that reason. It implies there some dishonesty. Granted, there is much confusion regarding words like 'faith' and 'God,' but the word 'spirit' is unambiguous even in modern parlance.
Sometimes.
It's also used in reference to attitude and behavior, as in the phrase, "That person has a lot of spirit", and in adjective "spirited."
Yes, it is. But true nonetheless.
Hardly. It's actually quite false.
Dictionaries are descriptive, not prescriptive. The shorthand form of that is this: if people are using a word in a way that is not in the dictionary, then it's the
dictionary that's wrong and needs to be updated. Thus, they are
very bad sources for such matters.
You keep citing the "dictionary definition", but you aren't saying
which dictionary you're using, nor are you citing which definition you're using. Here's the 7 from dictionary.com (on the noun form):
noun
1. the principle of conscious life; the vital principle in humans, animating the body or mediating between body and soul.
2.the incorporeal part of humans:
present in spirit though absent in body.
3.the soul regarded as separating from the body at death.
4.conscious, incorporeal being, as opposed to matter:
the world of spirit.
5.a supernatural, incorporeal being, especially one inhabiting a place, object, etc., or having a particular character:
evil spirits.
6.a fairy, sprite, or elf.
7.an angel or demon.
And every single one of these is correct, regardless of whether they are contradictory or not. While I do agree that equating spirit with "metabolism" is quite a stretch, I don't think there's any dishonesty or deception at play.
Now, did you know that the origin of the word, the Latin
spiritus, had connotations of "breath"? That means etymologically, it's conceptually cognate with such Eastern concepts like
prana and
qi. While I don't think the modern English word "spirit" has much to do with breath anymore, I think if there's any biological function that could be its equivalent, breath would be the best bet.