Explanation: Hopefully the title prompted you to add a day to some of the words in the grid. If you tack the word “day” onto 14A, 23A, 27A, 39A, 46A, 51A and 64A they sound like days of the week. The first letters of the clues for these entries spell WEAK DAY
Thought it was gonna be STRETCH naturally, and that I'd have to backsolve. Fooled me!
Led a bit astray for awhile by MONo vs MUNN, and KeepSATit. But just kept reminding myself: It's how they sound! Not the abbreviations! And it was fun to realize it was SADDER. Thanks, Lars!