is a specific kind of: garment.

is a broader term that covers: body stocking | bandeau, bra, brassiere | camisole, underbodice | chemise, shift, shimmy, slip, teddy | foundation, foundation garment | garter belt, suspender belt | long underwear, union suit | half-slip, petticoat, underskirt | singlet, undershirt, vest | underpants | underclothes, underclothing, underwear ... show more.

is the opposite of: outer garment, overgarment.