ஓங்காரப்பொரு ளொப்புயர்வில்லோயுனையாரறிவா ரருணாசலா
ஓங்காரப் பொருள் ஒப்பு உயர்வு இல்லோய் உனை யார் அறிவார் அருணாசலா
In plain words
You are what Om means. Nothing is like you and nothing is above you — which means there is nowhere to stand and look at you from. So who could know you? There is no one left over to do the knowing.
Word for word
Meaning of Om, you who have neither equal nor superior — who can know you? O Arunachala!