As a broker, we like truthful responses. If you are currently employed but plan on quitting, you are still employed at the time you apply. If at the time you apply for an account, you are not employed and have no source of income. you can say unemployed or retired, whichever one is accurate. The problem arises when your responses do not make sense. E.g. My income is $100,000/year and I'm unemployed, retired etc. Then we have to ask how the income is generated if you are unemployed or retired. There is no reason not to be accurate on your application.
If, as the thread is called, you want to Trade Full time-and you have no other employment, say you are a self-employed investor/trader.