LEXICAL WORD

In linguistics, a lexical word belongs to one of the "open" parts of speech, such as nouns, verbs, and adjectives. People coin new lexical words all the time, which is what is meant by "open": Open to new additions.

This contrasts with grammatical words, which belong to "closed" parts of speech such as pronouns, numerals, and prepositions. We have only to consider the lack of success of people trying to coin a gender neutral pronoun for English to recognize that such parts of speech are generally "closed" to conscious manipulation, although of course they do change through the unconscious evolution of the language.

Lexical and grammatical words often behave differently. Often grammatical words do not make full use of all the sounds in a language. For example, in some of the Khoisan languages, most lexical words begin with clicks, but very few grammatical words do.