noun
leggings; stretchy skin-tight trousers
Refers to stretchy, close-fitting trousers worn for exercise or casual fashion. In Japanese, this is the most common meaning.
See also: レギンス
ヨガのときはスパッツを履いています。
I wear leggings when I do yoga.
noun
Refers to the historical footwear accessory covering the ankle and instep. Less common in modern Japanese; often encountered in period contexts or fashion.
昔の紳士は靴の上にスパッツを着けていた。
Gentlemen in the old days wore spats over their shoes.
noun
Refers to protective coverings worn over the lower legs and shoes, mainly for outdoor activities. This meaning overlaps with spats but is more functional.
See also: ゲートル
登山ではスパッツを着けて靴の中に石が入るのを防ぐ。
When mountain climbing, I wear gaiters to prevent stones from getting into my shoes.