Infested with or containing many germs or microorganisms; likely to spread disease or infection.
From germ with the common English adjectival suffix -y, which turns nouns into descriptive adjectives. This colloquial form became widespread in 20th-century English.
Calling something germy is perfectly scientific in spirit—it uses the same root as germane (pertinent) because both describe something actively present and relevant, like germs in a petri dish.
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