'Twee' is a Briticism. It's general meaning is:

"...excessively or affectedly quaint, sentimental or mawkish, sometimes coupled with words like nauseatingly. It's a strongly negative word, and a very useful one, that is in common British use. It appeared at the beginning of the twentieth century to mean something dainty or sweet, a girly and gushing word."

That's a quote from Worldwidewords website.