caution

ot noun

1. A careful attention to the probable effects of an act, in order that failure or harm may be avoided The guideline expressed caution against excessive radiographic imaging.
2. One who draws attention or causes astonishment by their behaviour. Oh, that boy, he's a caution! He does make me laugh.
3. Precept or warning against evil or danger of any kind; exhortation to wariness; advice; injunction; prudence in regard to danger; provident care
4. Security; guaranty; bail.

fe’l verb

1. To warn; to alert, advise that caution is warranted.
2. To give a yellow card