Refers to the raised part at the back of a shoe or boot. Common in fashion and footwear contexts.
These pumps have such high heels that they're hard to walk in.
The heels on my new pumps are too high and hard to walk in.
The heels on these boots are worn down, so I'll take them in for repair.
Professional wrestling term for a wrestler who plays a villainous or antagonistic role, opposite of a 'babyface' (hero).
See also: ベビーフェイス
He's good at playing the heel in pro wrestling.
That heel wrestler got heavily booed by the crowd.
He has played the heel for years, exciting the fans.
She always wears heels to work.
The popular wrestler suddenly turned heel, causing a stir.
シール (sticker/seal) and ヒール (heel, as in shoes) sound similar in katakana but have completely unrelated meanings.
Borrowed from English 'heel'. The shoe sense is general; the wrestling sense comes from the same English term used in professional wrestling.