Thaddeaus is a distinctive boys' name in United States, ranking #11438 in 1999 with 5 recorded births. The name reached its all-time peak in 2001 with 10 births ranking #6885. Since 1996, the popularity has decreased by 28.6%. In 1999, approximately 1 in every 384,017 boys born was named Thaddeaus. FALLING Recent data shows the name is currently falling.