(informal) A new or rising talent or star; rising star.

(derogatory, slang, chiefly US) A general-purpose insult, often used to comedic effect due to becoming stale.

(idiomatic, ironic) Don't overexert yourself (in doing something that does not require much effort).

(idiomatic) Anything reputed to have the power to restore health and vitality or to restore a youthful appearance.

(idiomatic) Do something the way you want to, but be prepared for the consequences.

Interjection used to start a race, followed by "Get set, go!" or "Set, go!".

In a youthful manner.

(colloquial, nonstandard) Belonging to the multiple persons being addressed.

(of a female animal) Pregnant.

One should not depend upon a favorable (and typically overoptimistic) outcome to one's plans until it is certain to occur.