Junmai is the Japanese word meaning “pure rice.” This is an important term in the world of sake, as it separates pure rice sake from non-pure rice sake.
Junmai is brewed using only rice, water, yeast, and koji — there are no other additives, such as sugar or alcohol. Unless a bottle of sake says “junmai” (this will be written in Japanese as 純米), it will have added brewers alcohol and/or other additives.
There are sub-categories of Junmai Sakes - Junmai, Ginjos, and Daiginjos. The Junmai Ginjo can be viewed as more premium than the regular Junmais, and the Junmai Daiginjo as more premium than the Junmi Ginjos. However, this does not mean that the Daiginjos re the best - Daiginjos are very light in flavor while the Junmais are more bold. Daiginjos will pair well with very light foods (like sashimi and nigiri) as neither the food nor sake will overpower the other. Regular junmais will do great with stronger flavored foods, and Ginjos fall somewhere in between.
Nigoris are coarse-filtered sakes; small rice particles are kept in the sakes, creating the creamy taste and texture. Nigoris do especially well with spicy foods - the creaminess helping soothe some of the bite.