It's a classic!
The word classic is used a lot when related to fashion and style, yet there are two distinct meanings of it, and they are often either conflated or confused. So let's define Classic in its two distinct ways:
Classic Style - Personality Dressing Style
The Classic personality style is one of the personality-based dressing styles
Classic - when applied to the personality dressing styles harkens to the traditional corporate world and what was worn to work by men. Until World War I women didn't wear "classic" clothing. It was only when men went to war and the women took over jobs in the office and started wearing the styles of clothing men had been wearing to the office that Classic clothing became something that was included in women's wardrobes.
What you'll see in True Classic Personality style clothing:
- Symmetry - buttoned up the middle
- Smooth woven fabrics - fine woven wool suiting, crisp cotton shirts
- Solids - rather than too much print or pattern
- Patterns - a fine vertical pinstripe or chalk stripe
- Structure - collars, blazers, jackets and tailored pants
- Colours - cool neutrals - black, white, grey, navy (and a bit of light blue)
- Fitted - neither skin-tight nor loose and baggy, tailored to fit over the body without clinging
- Opaque fabrics - very little skin is shown
- Simple and Plain - low on embellishment and detail
When you think about a crisp white cotton button-up collared shirt, this is a classic personality garment because it comes from the world of corporate menswear. If you have a Classic personality style then you may love a crisp white cotton shirt, but if you don't then this garment has no place in your wardrobe (I've seen way too many of these that are not worn in wardrobes because they are on people's "must have" list).
Now a Breton navy and white striped tee is not a Classic personality garment, it's made from stretchy jersey and although it would be completely acceptable attire in most offices these days, it would have been considered scandalous to wear to the office under your suit in the 1940s!
This is because jersey (stretch) fabrics came from the world of underwear, not outerwear!
In fact, a Breton tee would come from the Relaxed or Natural Personality dressing style, which is a much more casual style that places a higher value on comfort and practicality along with ease of movement, which is why stretch fabrics are a core element of the Relaxed personality style. Which is one of the other six possible styles that you may be a combination of.
Fashion Classic - Fashion Trends, Fads and Classics
Classic when applied to fashion trends means a garment that changes very little over time in its construction and form. Think a camel trench coat, a blue and white striped Breton tee or a plain black kitten-heel pump.
That navy blazer, that chambray shirt, and a Chanel jacket are all fashion classics. The navy blazer would also be a Classic Personality style garment, but the chambray shirt is a Relaxed personality style garment (chambray being too informal a fabric and related to denim whose natural home is the Relaxed personality style). The Chanel jacket isn't a Classic Personality style garment as it's too texture, instead, it's an Elegant Chic Personality style garment. A silk blouse may feel like it's a classic too, but it too is an Elegant Chic garment, it's too soft and lacks the structure for it to fit into the Classic Personality style, add a pussy bow to that blouse and it becomes a Feminine Personality style garment.
Your white tee and a pair of denim jeans with a navy blazer may be a classic kind of outfit, but only the navy blazer is a Classic Personality style garment, the denim jeans and the white tee are both Relaxed Personality style pieces.
Someone who has a strong Classic Personality style will wear a white cotton button-up shirt rather than a tee. My father, who is strongly Classic Personality Style has never worn a t-shirt or even a polo shirt in his life. When he was working he'd wear his dress shirts and suits to work with a tie, and on the weekend wear an old dress shirt with the collar open, and a pair of suit pants that he no longer wore to work. If he was cold he'd don a v-neck wool jumper. He loved bushwalking, and his bushwalking clothes were just demoted casual clothing, so even older dress shirts and old suit pants. He's never worn jeans, tees or anything that comes from the Relaxed personality style in his life. Everything has been from the Classic Personality style. This is quite a different way of dressing than dressing in fashion classics.
You're a Combination of Personality Dressing Styles
Everyone is a combination of personality dressing styles. You may have Classic at your core (and if you like wearing fashion classics it's likely that Classic is somewhere higher up on your stack, as traditional Classic Personality style clothing doesn't change as quickly and is a less decorative way of dressing than some, more minimalist than maximalist), but there will be other influences on your style as well. You may like comfort and knits and add in Relaxed, or maybe a floral pattern or delicate detail from the Feminine, or maybe you like a bold colour or print from the Dramatic or possibly some asymmetry or unusual construction from the Creative. And of course you could be a Classic, Relaxed and Feminine with a hint of Creative (or any other of the myriad combinations). 
For example, my button-up shirt here is the closest garment to Classic in its construction and fabrication, but the bold stripe makes it a Dramatic Classic rather than pure Classic. The denim skirt is a fashion Classic, but it's a maxi version so a trend version rather than a purely fashion classic version. This outfit has elements of Classic, Relaxed, Dramatic, Feminine and Creative in its expression - and this is a completely normal way to dress as you are a unique and complex person who may feel too constrained in pure Classic, and too frumpy in purely Relaxed, and too prissy in purely Feminine, and too bold in purely Dramatic. But taking small elements of a variety of the personality dressing styles helps you to feel just like yourself in the best way possible.
From Bland to Brilliant: Develop Your Signature Style with 7 Steps
As you can see there are multiple layers to choosing what to wear to express your personality, which is why it's the very first step in my 7 Steps to Style program which helps you really determine what it is that you like in clothing and what you want to take from each of the Personality Dressing Styles so that you feel truly at home in your clothing and stop wasting money on the wrong sort of clothes that you won't end up wearing.
Further Reading:
Transforming Classic Style: Adding Pizazz Without Going Overboard!
5 Ways Meghan Markle Updates and Modernises Classic Outfits
Colour Personality - 1. Neutral - Classic
How to Make a Classic and Structured Outfit Softer and More Alluring
