blocking (n.)

A term used in classical TRANSFORMATIONAL GRAMMAR to refer to the non-application of a transformational RULE. A rule is said to be blocked if it cannot be applied to a DERIVATION because of the occurrence of a specific property in the PHRASE-MARKER. The term is also used in GOVERNMENT-BINDING THEORY to formalize the notion of what can act as a BARRIER. To be a blocking category, A must not be THETA-marked by a LEXICAL (l) category, and A must dominate B.

In MORPHOLOGY, the term refers to the prevention of a process of WORD-FORMATION due to the existence in a language of a word with the same meaning as the one which would have been formed. Although we may obtain curiosity from curious, English does not allow gloriosity, because glory already exists in the language, and therefore blocks it. This notion of SYNONYMY avoidance can also be extended to such cases as went blocking goed.