420 is said to be the international time to smoke pot. It has been said to have originated from police code for a marijuana bust but this is untrue. Some say that waiting until 4:20pm to smoke marijuana enhances your appreciation for the 'treat' :) Outdoor growers typically plant their outdoor crop on or around April 20th (4/20), which is said to be 'Stoners New Year.'
So 420 friendly means that she may not actually use marijuana, but she is ok with marjuana and its underlying culture.
"Clarity is defined as a state in which one fins them self when they go too long without good marijuana"