What does "Guardii Loo" mean?

Answer 1

Generally spelled 'gardy-loo', it's been mangled from the French 'Gardez l'eau', which means 'Look out for the water!' Those who lived on the second floor of buildings in large cities in Britain would yell that out before they dumped their chamber pots out the widow so passersby would have a chance to avoid what was coming down.

http://www.rotary.belux.org/en/news/telex001461.shtml

Answer 2

It sounds like italian , or italian dialect..
If so, then "guardalo" (could be "guardilo" ) means "look at him !".