You can add descriptions to properties which is very useful for general administration.
But this description is only displayed to end users from records if you hit the details button.
It would be very helpful if overlay text was displayed when you hovered over the property label (or an info icon) on HubSpot record views, HubSpot All Property view and Pipeline Dependent Property Forms.
That would be fine if we could add HTML and CSS to the HubSpot UX, but alas
we cannot 
Indeed, it would be super useful, particularly with conditional properties displayed when a deal moves from one deal stage to another !
Agreed on this. Would be extremely helpful for all the custom properties we use.
+1 on this! Small but impactful change/addition
This is a great idea especially when we have created quite a few properties for our deals.
Gah I am in immediate need for this right now 
the description should be desplayed at least when hovering over, but for me ideally it should be displayed underneath the name of the column in smaller font.
Absolutely, it would be incredibly useful, especially with conditional properties that display as a deal progresses from one stage to the next.
Really great idea that I would LOVE to see implemented!
Hi everyone, I’m Rachel, the PM for properties. Thank you all for taking the time to submit, upvote, and comment on this Idea. I’m happy to report that this Idea is now In Development! This means that our engineers are actively building this feature. The product development process is always filled with unexpected bumps and hurdles, so I can’t give a timeline, but I am confident in saying we’ll deliver this feature as soon as possible. All updates will be relayed on this thread, so stay tuned!