A word-group is the largest two-facet lexical unit comprising more than one word but expressing one global concept.
The lexical meaning of the word groups is the combined lexical meaning of the component words. The meaning of the word groups is motivated by the meanings of the component members and is supported by the structural pattern. But it’s not a mere sum total of all these meanings! Polysemantic words are used in word groups only in 1 of their meanings. These meanings of the component words in such word groups are mutually interdependent and inseparable (blind man – «a human being unable to see», blind type – «the copy isn’t readable).
Word groups possess not only the lexical meaning, but also the meaning conveyed mainly by the pattern of arrangement of their constituents. The structural pattern of word groups is the carrier of a certain semantic component not necessarily dependent on the actual lexical meaning of its members (school grammar – «grammar which is taught in school», grammar school – «a type of school»). We have to distinguish between the structural meaning of a given type of word groups as such and the lexical meaning of its constituents.
It is often argued that the meaning of word groups is also dependent on some extra-linguistic factors – on the situation in which word groups are habitually used by native speakers.
Words put together to form lexical units make phrases or word-groups. One must recall that lexicology deals with words, word-forming morphemes and word-groups.
The degree of structural and semantic cohesion of word-groups may vary. Some word-groups, e.g. at least, point of view, by means, to take place, etc. seem to be functionally and semantically inseparable. They are usually described as set phrases, word-equivalents or phraseological units and are studied by the branch of lexicology which is known as phraseology. In other word-groups such as to take lessons, kind to people, a week ago, the component-members seem to possess greater semantic and structural independence. Word-groups of this type are defined as free word-groups or phrases and are studied in syntax.
Word-groups are classified according to their syntactical pattern into predicative and non-predicative groups. Such word-groups as he went, Bob walks that have a syntactic structure similar to that of a sentence are termed as predicative, all others are non-predicative ones.
Non-predicative word-groups are divided into subordinative and coordinative depending on the type of syntactic relations between the components. E.g., a red flower, a man of freedom are subordinative non-predicative word-groups, red and freedom being dependent words, while day and night, do and die are coordinative non-predicative word-groups.
The lexical meaning of a word-group may be defined as the combined lexical meaning of the component members. But it should be pointed out, however, that the term «combined lexical meaning» does not imply that the meaning of the word-group is always a simple additive result of all the lexical meanings of the component words. As a rule, the meanings of the component words are mutually dependent and the meaning of the word-group naturally predominates over the lexical meaning of the components. The interdependence is well seen in word-groups made up of polysemantic words. E.g., in the phrases the blind man, the blind type the word blind has different meanings – unable to see and vague.
So we see that polysemantic words are used in word-groups only in one of their meanings.
The term motivation is used to denote the relationship existing between the phonemic or morphemic composition and structural pattern of the word on the one hand and its meaning on the other.