This ain't your grandpa's word square!

Question

^{An entry in Fortnightly Topic Challenge #43: Variety Crossword Grids}

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This is a regular word square:

C A R D
A R E A
R E A R
D A R T

As you can see, the words read the same across and down.

Now I have a word square for you to solve. Here are the clues, in top-to-bottom/left-to-right order:

1. Hold delicately, especially in one's arms
2. Stubborn, unyielding
3. Worse, as in an excuse
4. Came through the door

There's something odd going on with the grid. Your task is to figure out why this word square qualifies for the "Variety Crossword Grids" topic challenge, and provide a picture/rendering of the finished word square. Then read down the left-to-right diagonal for a description of what's happened to the words.

Answer 1

The filled word square:

And as we can see from the diagonal,

the words have been CRAMMED!