Many people are confused by the definitions and do not know which is easier to obtain, affirmative or defensive asylum.
Defensive Asylum
You are asking for asylum in response to a government attorney arguing for your deportation in Immigration Court. Asylum is your defense. This will likely require several hearings prior to your final one before the judge where you and your witnesses may testify on your behalf.
Affirmative Assylum
You are here on a visa or without status, and you are applying for asylum before your visa expires or you receive a notice to appear. You will only have to present your asylum application to a USCIS official who will decide your case, you will not go before a judge.
Generally speaking, it is harder to prove asylum defensively than it is affirmatively. However, in either case, it is best to have an experienced advocate by your side.