I am afraid that when I hear it (if I hear it) I may introduce palm to forehead aggressively (an action some of you might in fact encourage me to do):
Is there one word to express "not belong"? As in:
That book does not belong on that shelf. It belongs on this one with the other compilations of Manitoban poetry.
Or:
I really feel I don't belong here. I mean, everyone is dressed so nicely and speaks so properly, while I in my oversized plaid shirt mumble nonsensically.
Thus, I mean an antonym to belong in the sense of "used to say that someone or something should be in a particular place or situation" (from M-W).
Best Answer
The two example you give seem different to me. And getting that meaning in a single word is a challenge.
For the first example
Out of place could be used here, as in
Contracting the phrase to one word gives
The Oxford dictionary defines misplaced as 1.1 Not appropriate or correct in the circumstances
The second example
could also use out of place, but misplaced would be quite an unusual thing to say.
Alien could be used though:
The American Heritage Dictionary defines alien as 2. Belonging to, characteristic of, or constituting another and very different place, society, or person; strange.