Urusei Yatsura is a complex Japanese pun that is probably worth
explaining, since Rumiko is tremendously fond of puns, and liberally sprinkles
her work with them (as do most Japanese writers--puns are a linchpin of
Japanese humor).
Japanese is a wonderful language to pun in, since the
characters have pictorial meanings in addition to their readings. In the case
of 'Urusei Yatsura', the pun works like this: 'urusai', meaning 'noisy', or
'shut up', is usually written phonetically in the hiragana character set.
Takahashi substitutes the kanji (pictographic character) 'sei', meaning 'star
or planet'. This character is used when naming planets--eg. Mars is called
'Kasei' in Japanese (the 'ka' meaning 'fire'). 'Yatsura' is a somewhat
low-class term meaning 'rabble' or perhaps 'group of obnoxious people'.
So the first level meaning is simply 'Planet Uru Rogues'. Layering on the obvious
'urusai' implication, the second level meaning is more like 'Those
Annoying/Obnoxious Aliens from Planet Uru'.
All of these meanings are more are immediately perceived by the Japanese when
they read the title--alas, we can only feel a fraction of that impact. But it does
highlight the difficulties faced by translators of Takahashi's works--and Japanese
comics in general.