The adjective "funny" (from fun) is relatively recent:
"humorous," 1756, from fun (n.) + -y (2). Meaning "strange, odd, causing perplexity" is by 1806, said to be originally U.S. Southern (marked as colloquial in Century Dictionary). The two senses of the word led to the retort question "funny ha-ha or funny peculiar," which is attested by 1916. [...]
"diversion, amusement, mirthful sport," 1727, earlier "a cheat, trick" (c. 1700), from verb fun (1680s) "to cheat, hoax," which is of uncertain origin, probably a variant of Middle English fonnen "befool" (c. 1400; see fond). Scantly recorded in 18c. and stigmatized by Johnson as "a low cant word." Older senses are preserved in phrase to make fun of (1737) and funny money "counterfeit bills" (1938, though this use of the word may be more for the sake of the rhyme). See also funny.
[ Online Etymology Dictionary - etymonline.com ]
When I looked at the Cambridge, it struck me as a learner that "funny" doesn't seem much about humor anymore from the semantics point of view. I reproduce the helpful outline and the examples included with the "humorous" meaning:
funny adjective (HUMOROUS)
humorous; causing laughter:
Do you know any funny jokes?
I've never found Charlie Chaplin very funny.
It's a really funny film.
It's not funny - don't laugh!
Breaking your leg isn't funny (= is serious), I can assure you.
No matter how disastrous the situation there always seems to be a funny side to it.
Don't you try to be funny with me (= be serious and show respect), young man!
He was being funny but I think he was half serious.
A funny thing happened in the office today.
Her new book's hilariously funny.
His speech was full of inanities that were meant to be funny.
He's naturally funny - he doesn't even have to try.
funny adjective (STRANGE)
- strange, surprising, unexpected, or difficult to explain or understand:[...]
funny adjective (DISHONEST)
- informal dishonest; involving cheating:[...]
funny adjective (UNFRIENDLY)
- [after verb] UK informal unfriendly or seeming to be offended:[...]
funny adjective (ILL)
- [after verb] informal slightly ill:[...]
funny adjective (CRAZY)
- UK informal slightly crazy:[...]
[ Cambridge Dictionaries Online - "funny" ]
Personally, I would have been unsure about "A funny thing happened in the office today." But more important there is one meaning about humor and five variations on the "strange/not normal" theme; it does not speak about usage proportions though. On the other hand many compositions such as funny money/business/farm are quite not about humor.
This is about the origin and evolution of the "not humorous" meanings of "funny". The question is twofold:
- What is the (language) context for this taking shape in Southern U.S. in 1806 and is it just random or is there a reason this happened then(and there)? Is the Harper's magazine quote from the Century about how you feel when someone "doesn't send for you" related to that time and place?
- Back then, did the semantics of the word rapidly or gradually "shift" towards the not funny/strange meanings(dishonest, unfriendly, ill, crazy, not all informal anymore) and are those meaning expanding today at the expense of the "humorous" meaning; is that supported by anything from usage? Is "funny ha-ha or funny peculiar" still relevant or helpful to assess any of this?