i think it a sin only if the person that you call a liar is not a liar
liar
u can call them a user or liar i guess
a liar. they say liar so many times it begins to sound like lyra and liar are the same! :)
psycho
Normally a liar.
a liar
braggart
habitual liar
A very good liar!
A person who lies only when necessary can be described as a "compulsive liar" or "occasional liar."
A member of parliament is usually called a LIAR