The word "Casual" is very often used, and I want to touch on that because there's no written definition, and it's largely cultural and contextual. It's also relative and subjective, just like rich/poor, dry/wet, etc. What is casual to a CEO might be really dressy for a college kid. There's no written manual on what makes something casual or non-casual, but there is still expectations in society.
So, I've basically written up a 5-point scale to explain the different kinds of casual, based on what I observed.
1 is most casual, and 5 is least casual. And there are gray areas.
1 - Kiddy Casual
Hoodies, t-shirts with logos and designs, abercrombie or other clothes with explicit brand names shown, fake jewlery, sandals, sporting clothes, sweatpants, baseball caps. Flamboyant shoes like air jordans. Shorts. This includes stuff like "punk/goth" and "ghetto". Basically stuff that's cool in high school, but after college - not so much.
2 - Average Joe Casual
Jeans, solid color t-shirt, maybe a casual button-down or a polo shirt, shoes that are casual but more mature like Polo shoes maybe. Good for an adult going out to the supermarket or a movie theatre or anywhere without a specific dress code. A windbreaker maybe.
3 - Night-Out Casual
Jeans (only dark blue - not light colored), but also trousers, khakis, slacks are acceptable. A long sleeve buttoned shirt that's solid colored or has minimal designs. a sports and black leather slip-on shoes. Maybe a trenchcoat or a quality leather jacket. Good for going to a night club or fancy restaurant.
4 - Work Casual
Depends on the job. Lots of jobs nowadays are in between 3 and 4. But for an office job at Bear Stern let's say. But solid color work shirt (only worksafe colors like light blue). Tasteful tie. No jeans - slacks or trousers instead. Dress shoes.
5 - Formal
Even what diplomats and presidents/leaders often wear are technically 4.5's. Formal is what you wear at a wedding or funeral. Black and white only. Suit (no blazers).
A lot of men's style blogs say men should dress like a 3.5 to 4 wherever you go, but you will stand out and you don't need to. Most Americans dress like a 1 or 1.5, maybe a 2. To look sophisticated, clean, professional and not too overdone, it's probably best to dress like a 2.5 to 3 on a day to day basis. I think people in Europe are naturally better dressed. You'll look a little bit better than the average Joe, but you won't overdo it. And then, 3.5 to 4 on work or special occasions. Like on a date, I wouldn't be an over-impressor and try to be a 4, or be too casual at a 2, but a 3.
Sorry if this was long, but it just irritates me when people throw around the word casual without any specific meaning.
TECHNICALLY, everything that is not a 5 is casual. But some things are more casual than others. And something that is too casual for Obama to wear at a cabinet meeting might be really classy to wear on a night out to new york.
So, was my guide helpful or total nonsense? I'll let you decide. Do correct me where I'm wrong though.