'User' definitions:

Definition of 'user'

From: WordNet
noun
A person who makes use of a thing; someone who uses or employs something
noun
A person who uses something or someone selfishly or unethically [syn: exploiter, user]
noun
A person who takes drugs [syn: drug user, substance abuser, user]

Definition of 'User'

From: GCIDE
  • User \Us"er\, n.
  • 1. One who uses. --Shak. [1913 Webster]
  • 2. (Law) Enjoyment of property; use. --Mozley & W. [1913 Webster]

Synonyms of 'user'

From: Moby Thesaurus