Non licet - It is not allowed
Non liquet - It is not clear
Non mihi, non tibi, sed nobis - Not for you, not for me, but for us - the foundation of a good relationship

Non mortem timemus, sed cogitationem mortis

We do not fear death, but the thought of death. (Seneca)

Non multa, sed multum - Not many, but much. (Meaning, not quantity but quality) (Plinius)
Non nobis, Domine - Not unto us, O Lord
Non omne quod licet honestum est - Not everything that is permitted is honest. (Corpus Iuris Civilis)
Non omne quod nitet aurum est - Not all that glitters is gold
Non omnes qui habemt citharam sunt citharoedi - Not all those who own a musical instrument are musicians. (Bacon)
Non omnia moriar - Not all of me will die. (Horace)