First, let me say this questions is asking only about fairly recent loanwords (as in, the word (or something similar to it) exists in both languages). I'm not asking about very old loanwords that may have shifted in meaning in either/both languages.
As an example of what kind of loanwords I'm looking for, let me present:
das Handy
and der Smoking
in German (borrowed from English; try to guess the meaning before looking at the spoiler below).
cellphone
andtuxedo
, respectively.
Even though both are "borrowed" from English, the meaning probably isn't clear to an English speaker.
I am not referring just to loanwords where the meaning is slightly adjusted from the meaning in the borrowing language, for example:
sombrero
("hat" in Spanish, but a specific style of hat when borrowed into English).baguette
(I guess "rod" or "wand" would be the best translation? Also refers to the bread, because it has that shape. In English, refers exclusively to the bread.)
Is there a term for loanwords with a completely different meaning in the borrowing language (to the point that native speakers of the original language wouldn't understand)? Can anyone think of examples where English borrowed a word and did this? (I have trouble with this as an English speaker.) I do realise this might be fairly subjective.
If I've screwed up any terms, please let me know and I can edit this.