Past tense of blot; made a mark or stain on something, or absorbed liquid using blotting paper or cloth.
From blot (to make a spot or stain) plus -ed past tense suffix; used since medieval times for both accidental marking and intentional absorption.
Blotted has two very different uses: you can blot spilled wine with a napkin (absorb it) or a scandal blots your reputation (stains it), showing how one word can mean opposite actions.
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