1) conformity to the recognized standard of propriety, good taste, modesty, etc.
2) the recognized standards of decent or proper behavior
Decency is relative. I remember a story about an old woman who called the police on a college girl for wearing a bikini at a taco bell. That's the most inane definition of the word. How about this: Let's say I told you the president had a very fine pair of shoes worth one thousand dollars. Don't you consider that indecent that there's a man with a single pair of shoes that costs as much someone's monthly rent? One more example, have you ever observed a situation where someone used a bad word and someone else spoke out against it as indecent language? How about: it's indecent to impose your beliefs on others.
Now, if I'm going to say that it's indecent to impose our beliefs on others, than that makes democracy indecent if it's based on a majority making decisions for a disagreeable minority. And, if I'm going to say that it's indecent to own a $1,000 pair of shoes relative to the average rent, than perhaps it's also indecent to for me to drink clean water and eat healthy food when 2/3s of the world doesn't have adequate soil for basic agriculture.
Not only is decency relative, it's also absurd and it's ridiculous to attach negative or positive meaning to it because it cannot be done objectively. If you want to tell me a bikini is indecent, I can't accept that. Don't even explain why it's not decent, just skip to the part where you demonstrate that it does evident harm to others. If you can show how it does you harm, and possibly taking into account what redeeming value or alternate positive affects there might be, I will reconsider.
*Basically what it boils down to is a rule in society as opposed to a scientific law, something that is universally logical and enduring.
