Source: Ontario Small Claims Court - A Practical Guide (2011). p. 190 Bottom.
(d) Inflammatory Pleading
ยง9.15 A plaintiff or defendant in his pleading may make scandalous or in- flammatory references to the opponent. For instance, it does happen that either party will castigate his opponent as a "bare-faced liar". The motions judge will strike out the offending reference.
The quote above concerns Ontario law, but I intend my following question to concern advocacy in general (and not limited to a jurisdiction).
Adding 'bare-faced' to 'liar' does appear too affecting, bombastic, and pointlessly insulting, threatening. But when is it not an inflammatory pleading for a litigant to plead 'lying' or allege the other party as a 'liar'? Or should a litigant never use the morpheme 'lie' in a legal context? I ask not about judges because they have less to lose.