Umarell /uma'rɛl/ (oo-mah-rell), n; pl. Umarells. People in a community who offer all sorts of comments to those who are trying to get some work done, but who are not doing any work themselves.
Etymology and further details
Umarell is a word that entered Italian slang in Bologna and is spreading to nearby towns, occasionally even across Italy. It comes from the Bolognese for "cute/odd little man".
"Umarells" are those people, usually retired men, who spend time watching construction works, often holding their hands behind their back, occasionally commenting on what is going on, sometimes trying to tell the workers what to do.
With some Italian Debian friends, we realised that umarell is the perfect word to describe those people in a community, who offer all sorts of comments to those who are trying to get some work done, but who are not doing any work themselves.
I think that it is a word that fits perfectly, and since I'm likely going to use it blissfully anywhere, here is a page that temporarily explains what it means until the Oxford English Dictionary picks it up.