An insult against the King. The Oxford Pocket Dictionary of Current English (2008) defines this as: the insulting of a monarch or other ruler; treason. A fuller description of the term is found in Wikipedia.
Very few countries now have specific lèse majesté laws but treason is still a crime. The question that arises in Sri Lanka today is whether criticism amounts to treason. Those who have been following the debate may be able to discern for themselves where the official position lies, even if the officials themselves are quite unaware the concept itself.
This in turn raises further interesting questions, not least Quis custodiet ipsos custodes?