Guest Attire- What to say?

You're right. Your guests are adults. I would just say if someone asks you go with "cocktail attire" or just details

If it's not a big deal to you and will appease the MOB and FMIL, put something general on the website so you don't have to talk/think about it anymore.

Totally agree with you!

I think they'll know what not to wear... hopefully ! Lol. Never been to a wedding outdoors or indoors that someone under dressed

Let them figure it out. The only exceptions? True black tie, dress codes enforced by venues, weird terrains, outdoor weddings when people won't expect them.

I know how to dress and have for years, I do not need instruction.

On the other hand, there are those that do. I have seen more than a number of girls showing up thinking they are going clubbing. I have actually witnessed persons showing up in jeans. I have been there for women that felt it was acceptable to wear a short white dress to a wedding...yes, I said white and dress.

Possibly the family members have certain guests in mind that feel should be reminded. Not sure.

In any event...you could add something along the lines of "semi formal attire appreciated" or "formal attire requested", "Black Tie event". On and on. There are a million ways to add a little tiny snip it on the reception card or in the invitation at some point.

My bestie used a business card sized note for the name and address of the reception and added "semi formal attire requested" on the bottom in smaller font.

It worked out because it had the women talking about what everyone was going to wear.

I get it, you do not want to tell adults how to dress and most do not need that service from you. Most likely your family has witnessed situations where people should have been told what to wear and are worried about it at your wedding.

I don't think I've ever been to a wedding where someone wasn't wearing jeans and sneakers, and I've never been to one where it was appropriate.

Just because people should know how to dress doesn't mean they always do. I consider myself a good dresser, and definitely enjoy fashion, and I personally love getting guidance for events. I don't like being over or underdressed, and I don't feel condescended to when I get instructions.

We're going to put something, not sure what, on our website under the FAQs. It seems like a little much to put on our invites.

I know how to dress for an evening wedding, regardless of the day of the week on which it's being hosted. Actually, I know how to dress for an afternoon wedding, as well.

I certainly don't need a dress code imparted unless the wedding is a true black tie -- that, I need to know (but if you're starting it before 6:00 PM and have asked me to pre-order our entrees, I'll realize that I don't need to wear a gown and my husband doesn't need to wear a tux). I don't know why your mother and his mother have agreed on this topic, but they need to calm down.

ETA: I neglected to congratulate you on that Master's Degree. That's a huge achievement, and it will serve you well, decade after decade. Congratulations!

To me "work casual" is pants and a blazer. "Semi-formal" I have no idea what the person means. I once saw "dressy casual". I wouldn't go with a dress "code" per se because not everyone will have the same idea of what is requested. Trust people to dress appropriately. If they don't, you're not going to notice.