To make smaller.
To become smaller.
To lessen the authority or dignity of; to put down; to degrade; to abase; to weaken; to nerf (in gaming).
To taper.
To disappear gradually.
To take away; to subtract.
Lessened, reduced
The diminished Roman Empire never recovered from the sack of Rome.
Made to seem less important, impressive, or valuable
She felt diminished by the report card.
Reduced by a semitone