Thaddeus

It's derived from the Aramaic word "tadda", an appellation one would give to a close friend or younger sibling (literally, it means "breast" - but think of the phrase "bosom buddy" and you'll see why this makes sense). Henceforth, a very loose translation would be "friend".

"Thaddeus" comes from Aramaic "Thaddai" which means "braveheart" (a person of courage). This name was given by Jesus Christ to one of the Apostles, namely to Juda (do NOT confuse him with Judas the traitor).