“Underwear” is one of those nouns that can be singular or plural and can take a singular or plural verb. “There isn’t any clean underwear…” “There aren’t any clean underwear…”
And yet we say T-shirt (singular) and T-shirts (plural) although technically a T-shirt is underwear, too, since it can be, although not necessarily, worn under a shirt.
“Underwear” is one of those nouns that can be singular or plural and can take a singular or plural verb. “There isn’t any clean underwear…” “There aren’t any clean underwear…”
And yet we say T-shirt (singular) and T-shirts (plural) although technically a T-shirt is underwear, too, since it can be, although not necessarily, worn under a shirt.
Isn’t English odd?