warn
/ˈwȯrn/
verb
phrasal verb
to tell (someone) to go or stay away in order to avoid danger or trouble
The neighbors warned us off their land.
verb
to warn (someone) beforehand : forewarn
… in 1951, the network began to unravel, and two of its members, Donald Maclean and Guy Burgess, prewarned by fellow conspirators, jumped the night ferry to St.-Malo …