Telegraphing is the unintentional communication of your intended actions prior to performing them. This term is a carryover from Western boxing, which came of age when telegraphs were the fastest means of communication.
Telegraphs or “tells” are unintentional, reflexive physical actions; premeditated tells are actually feints or fakes. Tells are dangerous, because they are extremely subtle, and people are often unaware of their own telegraphing actions. These must be discerned by experienced training partners, before they are discerned by experienced opponents.
Tells are commonly associated with poker players, who must conceal their facial reactions to being dealt bad hands into order to bluff their opponents. Martial artists must do the same, and avoid looking at intended targets and/or “winding up” techniques by pulling away before executing them. Likewise, slow techniques are essentially telegraphed, since they offer the opponent the time they need to discern what is happening, and how to counter it.
Once identified, telegraphing can be minimized with conscious, deliberate practice in front of a mirror. The ability to suppress telegraphing is a hallmark of professionalism, because mastery isn’t about doing complicated things; it’s about doing simple things extremely well.