Auch eine Kennzeichnung der informellen Sprachebene hielte ich für angebracht.

mit Jalapeno
Die Amerikaner sagen zu Müllereimern ja auch trash can statt litter bin oder rubbish bin. R. ist typisch GB.

Jalapeño: agree that in AE there is no verb 'to rubbish'

in AE it's "to poo-poo" something (an idea, a plan etc.)
im Sinne von "etwas als Unsinn abtun, runtermachen"

"verreißen" würde ich im Deutschen nicht auf der informellen Sprachebene ansiedeln. Außerdem bezeichnet es im Gegensatz zum Englischen ausschließlich einen schriftlichen Kommentar in einem Massenmedium zu einem Film, einer Publikation oder einer öffentlichen Aufführung (und nicht etwa zu einer einzelnen Idee oder einem Vorhaben).

Stimme Rodos in beiden Punkten zu.

'schlechtmachen' fällt mir ein - ist immer noch nicht besonders ugs., aber besser als 'verreißen', was ich auch als fast schon Fachausdruck empfinde. Vielleicht fällt euch noch mehr ein?

Ugs.: runtermachen, niedermachen


Gerade sehe ich, dass inapina "runtermachen" in #4 schon erwähnt hat.

Oh, stimmt, das habe ich irgendwie auch völlig übersehen, sorry. 'runtermachen finde ich gut.

LEO:
to pooh-pooh sth. - über etw.[Akk.] geringschätzig hinweggehen
Dictionary: pooh-pooh

Just for the record, #4 isn't correct. That verb is spelled with an H, 'pooh-pooh.'

The LEO translation for it may not be quite right -- I too would have thought of 'abtun,' or indeed 'runtermachen,' because when you pooh-pooh something, you mean that you don't believe it, in a sarcastic or dismissive way.

'Poo' or 'poo-poo' without an H is a baby word for Aa, Kacke, etc. So you don't want to confuse the two. (-:

There is a verb in AE 'to trash sth.' The most common sense is to throw something away, put it in the trash: He trashed his first design and started over. 

But I think it can also be used to mean to run something down, criticize it, dismiss it: Stop trashing all my good ideas! I was going to look for a few examples, but the Uni Leipzig website is down for maintenance; maybe another time.

#9: Nevertheless, the spelling "poo-poo" seems to be used in the figurative sense to some extent: https://www.google.de/search?q=%22to+poo-poo%...
After all, in spoken language you can't tell the difference :-)

When it comes to spelling, never trust G**gle, only a dictionary. If you can find it listed as a variant, you could suggest adding it, but I think most teachers and editors would still consider it wrong.

Wortschatz Uni Leipzig:
• Dominant media routinely focus on counterfeit issues, ignoring or trashing progressive options in the process
• Students were basically trashing and gossiping about the teachers
• have suddenly embraced the assertion that women can do it all, even those conservative Republicans who have made careers out of trashing that notion
• rubbed it in by trashing the fashion icon's widely publicized Wimbledon ensemble
• wise to write a piece that isn't full of "trashing Britney".
• makes a living trashing celebrities
• We have disagreements ..., but it's a group of professional people and we're not busy trashing one another
• His campaign is about trashing the opposition, Karl Rove-style
• you ended the relationship for the right reasons, and nobody was unnecessarily trashed or emotionally beat up
• the studio might want to throw more money at the universally trashed special effect that was supposed to make P. sparkle magically in the sunlight but left him looking merely sweaty
• Automotive writers roundly trashed the Edsel
• He's trying to rehab his image before his new (and critically trashed) film comes out
• He was trashed for showing up to the Iowa State Fair in Gucci shoes and riding around in a golf cart instead of talking to voters
http://corpora.informatik.uni-leipzig.de/cgi-...

Here, belatedly, are some examples for 'to trash' in a similar sense in AE.