A longtime is a period of time that something or someone has been around for.
When we talk about the word "longtime," it's often used to describe relationships, jobs, or experiences that have lasted a long while. For example, if you've been friends with someone since childhood, people might say you've known them for a longtime. Or, if you've worked at the same company for many years, you can refer to your time there as a longtime employee. Sometimes, "longtime" is used in a more affectionate way, like saying "I've been waiting on that order for a longtime!" meaning it's taken an excessively long time to arrive.
Having endured for a long period of time.
Example: My longtime friend, since birth actually, called and gently broke the bad news to me.
Having been for a long time
Example: longtime married
