Sometimes anthy does not contain a word/definition and keeps converting the hiragana in non-usable kanjis. In order to have it convert the word into the kanji-word you wish, do (in a Debian based distribution):
sudo apt-get install kasumikasumi -aSpelling: 今日中Sound: きょうちゅうFor multiple definitions this way might be annoying. At the moment I just know this way.