"Semantic"?
Nah, you can't have a semantic disagreement over just one word. All you can have is a definitional agreement. And there, bunkie, I got ya: My definition of "lie" can be found in a dictionary. Where in the universe did you get yours?
Wikipedia has a nicely comprehensive definition:
A lie is an untruthful statement made to someone else with the intention to deceive. To lie is to say something one believes to be false with the intention that it be taken for the truth by someone else.
A lie involves the use of conventional truthbearers, (i.e., statements in words or symbols) and not natural signs. Intentional deceit involving natural signs, such as wearing a wig, shamming a limp, or wearing a fake arm cast, is not usually classed as "lying", but as "deception".
A true statement may be a lie. If the person who makes the true statement genuinely believes it to be false, and makes the statement with the intention that his audience believe it to be true, then this is a lie (see Jean-Paul Sartre, Le Mur (1937)). When a person lies he or she is intentionally untruthful, but he or she is not necessarily making an untrue statement.
You can speak in a made-up language if you want, but don't be surprised if people understand you according to the formal and public definitions of the words you use. You're responsible for your use of words with such well-understood meanings, and cockeyed personal redefinitions don't get you off the hook. Ignorance of the dictionary is no excuse.