warn 
/ˈwoɚn/ verb
warns; warned; warn·ing /ˈwoɚn/ verb 1 : to tell (someone) about possible danger or trouble [+ obj] ▪ I had been warned about the difficulties of the job. ▪ She warned me that the stove was still hot. ▪ The company has warned (investors) that its profits are likely to be lower in the coming year. ▪ “This won't be easy,” he warned. ▪ Nobody warned me about the dangers. [no obj] — usually + about or of ▪ The book warns about/of the dangers of not getting enough exercise. 2 : to tell (someone) to do or not to do something in order to avoid danger or trouble [+ obj] ▪ I warned him to be careful, but he didn't listen to me. ▪ She warned us not to go too close to the fire. ▪ We were warned against using [=warned not to use] the faulty light switch. [no obj] — usually + against ▪ She warns against making changes too quickly.
warn off [phrasal verb]
warn (someone) off or warn (someone) off (something) : to tell (someone) to go or stay away in order to avoid danger or trouble
▪ The neighbors warned us off their land.
▪ The neighbors warned us off their land.
