8 down
Reaffirmed
commitment,
thus
made
pillow
much
softer
(7,4)
Reaffirmed commitment, thus made pillow much softer (7,4)
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The whole clue is the definition (& lit or double definition).
How the clue works
The definition is Reaffirmed commitment, since to double down means to dig your heels in and strengthen your position. But the beauty here is that thus made pillow much softer works just as well as a definition — a pillow stuffed with twice the down would indeed be considerably cosier, so both halves of the clue define the answer simultaneously.