Hi... salaam. The word you asked about is مُولّي. Dictionaries are not going to be very friendly to you, so you should read the rest of the surrounding verses. There, you'll see this word used in other contexts and it tends to mean something like "turn towards". But, to search for this word in an Arabic dictionary:
- Look it up under the root: ولي . The مُ is a prefix that makes the word grammatically a participle (a noun derived from a verb but acts as an adjective. LOL i don't make these rules, i just relay them!)
- Since the Quran is a pre-classical Arabic text, you should use a pre-classical Arabic dictionary. We typically use Edward Lane's Lexicon at ejtaal.net. You can even type "w l y" and it'll bring you to the entry for all words built from the root w-l-y. The site is a little hard to navigate, but click on "Arabic Almanac", scroll till you see Lane Lexicon Supplement. From there go back 2 pages. Ridiculous, I know, but the dictionary is invaluable and worth the suffering. Try the mobile app as well.
- However, in this case, you won't find the word, because Edward Lane died before completing his work. So his nephew tried to complete it, but there are many gaps. Welcome to the goose chase.
- Arabic dictionaries presume you understand something about word relationships. Remember we said the participle is derived from a verb, but acts like an adjective? Let's look at the entry for Form II ولّى. There we see the verb has many meanings, but basically 2 general ideas: avoid, retreat to. Now, because we know it's an active participle, we can reverse engineer a plausible meaning as "one who avoids".
- But now we have to consider the context, because words don't have meaning in isolation, rather meaning comes from usage. The verse reads ولكلّ وجهةٌ هو مولّيها. An interpretation might be: "Everyone has a direction towards which he is turning."
There's a subtle connotation here that suggests "turning towards for protection", perhaps political, physical, or otherwise.
So these are some of the steps you can take for other words in the Quran as well.