Mendō is a Chinese-style compound written 面倒 (literally 'face fall') and has the meaning 'bother, nuisance'. It is not actually a Chinese word; it is a native Japanese coinage in the form of a Chinese compound.
The following notice directed at mobile phone users asks them to use their phones near the entrance of the restaurant.
The following sign writes mendō in hiragana as めんどう (as part of the word mendō-mi or 'looking after').
This is fairly atypical and in a way eye-catching because it uses almost all hiragana. (The English 'Secure After Service' is Japanese-style English meaning 'Good after-sales service'.)
A Google search in August 2003 finds that the use of Chinese characters to write 面倒 is standard, but hiragana is also used quite commonly.