What do they mean?
It sounds lame.
It's lame.
You're lame.

Question

Answer

Lame means 'weak'.

A lame excuse is one that nobody will believe.
A lame joke is one that nobody will laugh at.

If you say 'You're lame' it means 'You're useless'.

Answer

But it is not my position as a commoner to punish anyone by this impolite words; otherwise, both are wrong and incorrect to insult people or pretend educators / police officers.

Answer

Just a impolite word. But Su.Ki. is right sounds extremely harmful whether suffering from nature or accident.