Superlative form of germy; most contaminated with germs or containing the most microorganisms.
From 'germy' (full of germs) + superlative suffix '-est'. Colloquial English formation that became popular in the 20th century, especially in advertising and public health messaging.
Germiest is a perfect example of marketing language—'germiest doorknob in the office' became a trope in cleaning product ads to create anxiety, even though most doorknobs aren't actually dangerous and your immune system handles everyday germs just fine.
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