What term retirement usually denotes to is, to stop working. People often don't like job, so to retire usually tends to be on top of the list. However, if one likes what he does, he will do something similar to pass the time even after retirement.
IMO, retirement for me is not to totally stop working at all and chill for the remaining days or years of your life, but for me it's like freeing yourself from stressful job usually when you're working under a company for how many years without being able to have enough time for yourself or your family. Retirement for me is being able to do whatever you want without worrying about finances in general, because you have already saved enough for your retirement including insurances and investments.
Though most people is looking forward for their retirements because they don't like their jobs, but for me it's not that way. I actually like my job and it's pay but I'm also looking forward for retirement so I could finally enjoy and control my time without being worried and stressed out on my job. We all want to live a happy and peaceful lives and the only way we know we can achieve that is when we don't need to work to earn money anymore. Being rich might be an answer to that, but rich people do also have a lot of stressful problems financially.