Of a person, having a lot of hair on the body.
"After shaving his chest for years, John was shocked to discover he was actually quite hairy when he finally let it grow back."
In plain English: Hairy means having a lot of hair growing on your skin or body.
"The old man has very hairy arms after spending all summer working in the garden."
Usage: Use "hairy" to describe someone who has abundant body hair or, more commonly today, to characterize a situation as dangerous, difficult, or suspenseful. Avoid using it simply for general unattractiveness unless you specifically mean an excess of physical hair.
The word hairy comes from Middle English, where it originally combined the word for hair with a suffix meaning full of or covered in that substance. While its primary definition has always described something covered in hair, the secondary sense of "terrifying" likely developed as a blend of the phrase "hair-raising" and the idea of being scary.