That is what is meant when phraseological units are said to be characterised by semantic unity. In the traditional approach, phraseological units have been defined as word-groups conveying a single concept (whereas in free word-groups each meaningful component stands for a separate concept). [1]
Conclusion
Phraseology represents expressive resources of vocabulary. In standard spoken and written English today idiom is an established and essential element that, used with care, ornaments and enriches the language. [1]
Used with care is an important warning because speech overloaded with idioms loses its freshness and originality. Idioms, after all, are ready-made speech units, and their continual repetition sometimes wears them out: they lose their colours and become trite clichés. Such idioms can hardly be said to "ornament" or "enrich the language".
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