The problem of word-building is associated with prevailing morphological word-structures and with processes of making new words. Semantics is the study of meaning. Modern approaches to this problem are characterised by two different levels of study: syntagmatic and paradigmatic. On the syntagmatic level, the semantic structure of the word is analysed in its linear relationships with neighbouring words in con-nected speech. In other words, the semantic characteristics of the word are observed, described and studied on the basis of its typical contexts. On the paradigmatic level, the word is studied in its relationships with other words in the vocabulary system. So, a word may be stud-ied in comparison with other words of similar meaning (e. g. work, n. — labour, n.; to refuse, v. — to reject v. — to decline, v.), of oppo-site meaning (e. g. busy, adj. — idle, adj.; to accept, v, — to reject, v.), of different stylistic characteristics (e. g. man, n. — chap, n. — bloke, n. — guy, n.). Consequently, the main problems of paradig-matic studies are synonym, antonymy (see Ch. 10), functional styles. Phraseology is the branch of lexicology specialising in word-groups which are characterised by stability of structure and trans-ferred meaning, e. g. to take the bull by the horns, to see red, birds of a feather, etc. One further important objective of lexicological studies is the study of the vocabulary of a language as a system. The vocabulary can be studied synchronically, that is, at a given stage of its develop-ment, or diachronically, that is, in the context of the processes through which it grew, developed and acquired its modern form . The opposition of the two approaches accepted in modern linguistics is nevertheless disputable as the vocabulary, as well as the word which is its fundamental unit, is not only what it is now, at this particular stage of the language's development, but, also, what it was centuries ago and has been throughout its history.