You're a liar.
あなたは嘘つきだ。
You are the biggest liar.
You are all liars.
You guys are liars.
You are morons.
You guys are idiots.
You guys are stupid.
You're morons.
You're all morons.
You are a fool.
You're a liar.
You are hasty.
You are naughty.
Your inferiority complex makes you think [say] that.
You are a fool.
You are a coward.