Hmm. An older woman liking a significantly younger male is called a cougar. This is quite slangy.. And anyone over 18 liking anyone younger than 18 is called a pedophile. This isn't considered slang, really. Usually the age difference in this situation must be quite large. And to ask him/her out suggests the prospect of dating but does not necessarily imply it. Because if you ask someone out, you bring up the possibility of dating but he/she can still reject you. Whereas go out and dating mean basically the same thing, but going out is a slang term and doesn't necessarily refer to dating. ex. I went out with him for a month but then I realized he wasn't right for me. (implies dating) versus I'm going out with my friends tonight. (This implies just going out of the house to have fun.)

Someone who likes another person under 18 is not called a pedophile. It depends where in the world you are. Every country has a different law on the Age of Consent. In the UK you're only a pedophile if you like someone who is under the age of 16 or have sexual relations with someone who is under the age of 16 when you are 16 years or older.

Emily and Michael are both correct.

An older man that likes to date/marry young women is called a sugar daddy. A man that likes older women is a toy boy.