Ok, 'generation' in this context means everyone in a country who was born around the same time. For example, I was born in 1970, so people born around the same time are in my generation. I don't think there is a specific date range. But say roughly anyone born from 1965 to 1975 might be the same generation. Therefore it I said "my parents' generation" that would be people born roughly the same time as my parents. 'Jilted' in this sense means a promise was made, but the promise was broken (so similar to the idea when getting married). So 'jilted generation' means a whole group of people who were born around the same time grew up believing something (for instance, that the would be able to get well paid jobs or be looked after by the state in some way), and when they became adults they found this was not true. 'Music for the Jilted Generation' was an influential music album by the Prodigy, and this helped the phrase 'jilted generation' become more widespread. In fact, I am going to listen to this CD now -thank you for reminding me of it!