Noun
The abstention from harmful activities, foods, and so on.
(philosophy) The stance that the nature of reality is unknowable because all information comes through the senses, which are unreliable.
(philosophy) The denial of higher-level meaning beyond physical existence; materialism.
(philosophy) The belief in the existence of entities and events within a domain that can only be defined in terms of what it is not.
Source: en.wiktionary.org