Full Idea
Words in their primary or immediate signification, stand for nothing, but the ideas in the mind of him that uses them.
Gist of Idea
Words stand for the ideas in the mind of him that uses them
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 3.02.02)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.405
A Reaction
This is notorious and usually dismissed contemptuously. However, if the ideas themselves 'stand for' reality, our words are not just trapped in mental space. If my mental space contains things, presumably we can name them.