Wearing a T-shirt.

Alternative form of hairshirted

Wearing a dress shirt.

A lightweight shirt without buttons, usually with short sleeves and no collar. Often made of cotton and frequently bears a picture or slogan. / An undershirt.

A casual, usually short-sleeved, shirt with a protruding collar and a small number of buttons extending a short distance below the collar (and not all the way down the front of the shirt).

Alternative spelling of T-shirt

(idiomatic, informal) One who is pompous or self-important, especially one who is officious in a position of authority. / (usually hyphenated) Used attributively.

(bodybuilding) A sleeveless shirt tailored to display the muscles of the body.

A method of indicating team membership, typically when played by boys or men in informal sporting contests, in which the members of one team (the "skins") remove their shirts and play shirtless, while the others (the "shirts") leave their shirts on.

A polo shirt.