What is the meaning of "مُوَلِّي"?

The word مُوَلِّي appears in Quran verse 2:148. I have read a few translations of the verse (e.g. [here](http://corpus.quran.com/wordbyword.jsp?chapter=2&verse=148)) but I still don't have a good understanding of what the _word_ means. I looked it up on [المعاني](http://www.almaany.com) but it is not there. What is the meaning of the word? I am not looking for the translations of the verse, I know them. I am trying to understand the verse better by understanding the meaning and the usage of the word in Arabic.