user

noun6

1. •
   One who uses or makes use of something, a consumer or client or an express or implied licensee (free user) or a trespasser.
2. •
   A person who uses drugs, especially illegal drugs.
3. •
   A person who uses a computer or a computing network, especially a person who has received a user account.
4. •
   An exploiter, an abuser (a person who exploits others, that is treats and regards people unfairly, selfishly or unethically).
5. •
   (Internet, informal) Clipping of username.
6. •
   (old-fashioned) In land law, meaning either 1. or 2. above or use. Usually in singular form to mean use wherever there is assiduous re-use of precedents and aloof textbooks verbatim.

noun1

1. •
   (slang) Someone who uses the R programming language.