When we wish to inform someone about the details of a particular theme, topic, item or person - I'll give you the heads up about the new policy. The idiom appears to have a military origin - a heads up indicating that an important announcement was pending.
|An early citation for the contemporary use of 'heads up from 1977|
In recent years, however, 'to give a heads-up' has become synonymous with the less glamorous 'inform'"In a message characterized as a 'heads up alert', intelligence officials warned ... that Arab diplomats had suggested that Ambassador Andrew Young meet with a Palestine Liberation Organization official." The Washington Post, August 1979
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