Spanking my kid?

She may need to see a psychiatrist in that case. If you guys have tried things and none of it is working, it's possible she's dealing with an ongoing mental health issue. 

Yet you keep posting fake stories about your imaginary children with this sick topic attached to them.  You need serious mental help!

Spanking her is not going to kill her. A swat on her butt is going to tell her that you are now meaning business and she will calm down. Trust and believe~ millions of kids have been spanked over the years and have grown up to be wonderful people, not the traumatized trolls that people assume them to turn into. 

Look up "baited question" in the dictionary and check if your picture is displayed.

good parents always spank their kids, bad ones don't 

Start by talking with your pediatrician and read Have a New Kid by Friday by Dr. Kevin Leman.  Here are some things to consider:

1. Spanking without a clear philosophy is just hitting a child, and can do more harm than good. It really is NOT a necessary form of punishment or correction. A defiant child will not respond well to spanking.

2. A defiant child (not just strong-willed) may have a mental health issue.  Sorry.  Read up on Oppositional Defiant Disorder and Conduct Disorder see if these match your child's behavior and response when asked to do something they don't want to do.

3. Kids act out because they are testing boundaries. If acting out gets them what they want, they will continue to do it.  If they find their technique isn't effective, they will often be able to change their behavior.  If you child is unable to control their temper or modify their behavior, professional intervention may be required.  

Often loses temper

Is often touchy or easily annoyed

Is often angry and resentful

Often argues with authority figures or for children and adolescents, with adults

Often actively defies or refuses to comply with requests from authority figures or with rules

Often deliberately annoys others

Often blames others for his or her mistakes or misbehavior

Has been spiteful or vindictive at least twice within the past 6 months[12][13]

Give it a try. Othet4wise she needs a psychiatrist.

Never found a reason to spank my kids, but then again. They didn't behave in that manner either.  The mean to her siblings is a reflection of what has happened in the home, sorry. But that is how this comes about provided there are not any underlying issues.  The home work is common, usually is a result being on the wrong bio schedule, some sort of disconnect with the actual work, or the set up and whom she is doing the work with.  That is something you fix with figuring out the real issue, not punishment.  You are right, a couple of swats sometimes fixes things, short term. Figuring out the real issue before it's too late, and then figuring out the proper way to adjust to it. Is the long term solution.