en_tn/jer/25/18.md

a waste

Another possible meaning is "an object of horror" or "a terrifying thing."

an object for hissing and cursing

The word "hissing" refers to a sound that shows strong disapproval. Both "hissing" and "cursing" can be translated with a verbal phrase. Alternate translation: "an object at which people hiss and which they curse"

they are at this present day

Possible meanings are that this phrase 1) refers to the time when the book of Jeremiah was written and some time after Jeremiah had proclaimed this prophecy or 2) means that the things about which Jeremiah prophesies here have already started to happen.