Like a lot of the definitions here, someone is rachet if they are undesirably trashy in a ghetto sort of way. Where this term comes from is it's a rhyme (perhaps a mis-hearing) of "wretched."
Becca looks fine, but she'll straight-up pick ya pocket for it. She rachet.
An angry women with a attitude problem and no morals these kind of women are what u would call lower class women with the mindset of a walnut and known To disturb the peace ,all for the wrong reasons.....also known to stalk friends and anyone she associates with