Latin non, not.
This prefix is more widely used to form negatives than any other. It is freely added to nouns, adjectives, and adverbs, and also to verbs used to form adjectives. In general the sense is neutral, without the implications often present with compounds in a‑, in‑, or un‑; for example inhuman, non-human, and unhuman all refer to something lacking human qualities, but the first is usually pejorative, implying cruelty or barbarism, while the latter two are neutral; amoral and immoral usually imply a value judgement, while non-moral does not.
However, negatives in non‑ can contain the idea of pretence, inadequacy, or unimportance, as in non-event, non-story, non-hero, non-issue. Some adjectives formed from verbs have a sense of not causing something (non-crease, non-skid, non-stick), or not requiring something (non-iron).
A very few further examples in various senses are: non-believer, nonconformism, nonentity, non-fattening, non-linear, non-negotiable, non-partisan, non-returnable, nonsense, non-smoking, non-stop, non-uniformly, non-violent.