If you say something that I don't agree with, but I don't want to fight about it, I might respond whatever . Usually, the point of using whatever is to indicate that you don't think that what was just said is worth responding to, and you quietly refuse to engage with it. Oh well is similar - it mean that you resign, quietly, from struggling. But with oh well , you are probably responding to the state of the world, rather than to a particular person. Fraternities and sororities are college-based social clubs which have a long history and a mixed reputation.
Frats tend to be more visible, and sometimes more notorious.
The membership of both sorts of clubs are called greeks , because of the tradition of using Greek letters to identify them. Guys trying to get in to a frat are called pledges . Hazing has been controversial recently. Terms like fratboy and frat rat are considered insulting. Places on campus have their own distinctive names.