I like to think of this as four quadrants around two axes. Low fat/low muscle is simply skinny. High fat/high muscle is the "big guy/gal" look that I associate with laborers. Low fat/high muscle is an athletic look; unhealthy in extremes (bodybuilding) but generally desirable. High fat/low muscle is skinny fat, which I associate with sedentary knowledge workers.
[0] And that, at least somewhat, tracks visual perceptions. Nobody looks at me with a shirt on and believes I need to lose weight, because 10-15lb isn't _that_ much extra on a tall frame. If I were 40-50lb overfat then that would be painfully obvious regardless.
My actual methodology is pretty crude though -- when I was 15lbs lighter I had borderline visible abs and other visual indicators of being around the 15-20% body fat mark, and aside from gaining weight I don't have any reason to believe I've had any notable muscular atrophy since then, so I'm estimating the actual excess fat in that ballpark. It's be easy for numbers to be off 10lb or more, but even then it'd still indicate the overfat surplus being much less than the overweight surplus.
A better methodology uses calipers and various skin measurements to estimate true body fat percentage.
"Overweight" can mean the same thing for weight, but it also refers to those with a BMI specifically between 25 and 30, and those with BMIs greater than 30 are classified as "obese".