During Son Gohan's pivotal fight against Boo - essentially an ancient jinn, whilst he has attained a more powerful form and Gohan himself has awoken his latent qi, he spouts an insult:
ウスノロ…
Usunoro...
This has been infamously translated as "retard" by Stephen Simmons as the official North American subtitles for the video release.
The term is more ordinarily spelled 薄鈍 literally meaning "diluted (and) foolish", but translating to "simpleton/halfwit/fool."
Whether not any newer releases of the series have changed this is something I do not know.