warn·ing 
/ˈwoɚnɪŋ/ noun
plural warn·ings /ˈwoɚnɪŋ/ noun 1 : something (such as an action or a statement) that tells someone about possible danger or trouble [count] ▪ She gave me a warning about the difficulties of the job. ▪ There were storm warnings [=warnings that a storm was approaching] issued for the area. ▪ She issued a stern warning against making changes too quickly. ▪ Let that be a warning to you. [noncount] ▪ We had no warning of the dangers that were ahead of us. ▪ Without any warning she turned around and ran. ▪ The storm struck without warning. 2 [count] : a statement that tells a person that bad or wrong behavior will be punished if it happens again
▪ I was stopped for speeding, but the policeman just gave me a warning.
▪ I was stopped for speeding, but the policeman just gave me a warning.
fair warning — see 1fair
— warning adjective always used before a noun
▪ A warning bell rang before classes started. ▪ The policeman fired a warning shot. ▪ Falling prices may be a warning sign of a recession. [=may indicate that a recession is coming] ▪ the warning signs of cancer
▪ A warning bell rang before classes started. ▪ The policeman fired a warning shot. ▪ Falling prices may be a warning sign of a recession. [=may indicate that a recession is coming] ▪ the warning signs of cancer
