Sometimes people refer to the Jehovah's Witnesses as 'Jehovahs' instead of their real name.
Jehovah's Witnesses believe the word Jehovah is God's name. So when someone refers to them as 'jehovahs', it's not appreciated. To them God's name is sacred. The believe there is only one God Jehovah, not many Jehovahs.
They are 'Witnesses of Jehovah', not Jehovahs. Referring to them as Jehovah's Witnesses is fine. Or Witnesses for short is ok too.
Of course most people don't mean any harm. They are merely shortening the name full name because they don't know the meaning of this religion. Once they understand that calling the Jehovah's Witnesses 'Jehovahs' is offensive, most people are happy to show respect and refer to them by their proper name.
A Witness of Jehovah is someone who dedicates their life to serve their God Jehovah and what is believed to be 'His Organization', i.e. the Watchtower Society. Is Jehovah the same as Jesus? No. Jehovah is thought to be God's name. Jesus is believed to be God's Son.
Since Jehovah's Witnesses don't believe in a trinity, they believe that Jehovah and Jesus are separate individuals. They don't believe that Jesus is God.