The meaning of a compound word is made up of two components: structural meaning of a compound and lexical meaning of its constituents.
Compound words can be classified according to different principles.
1. According to the relations between the ICs compound words fall into two classes: 1) coordinative compounds and 2) subordinative compounds.
In coordinative compounds the two ICs are semantically equally important. The coordinative compounds fall into three groups:
a) reduplicative compounds which are made up by the repetition of the same base, e.g. pooh-pooh (ïðåíåáðåãàòü), fifty-fifty;
b) compounds formed by joining the phonically variated rhythmic twin forms, e.g. chit-chat, zig-zag (with the same initial consonants but different vowels); walkie-talkie (ðàöèÿ), clap-trap (÷åïóõà) (with different initial consonants but the same vowels);
c) additive compounds which are built on stems of the independently functioning words of the same part of speech, e.g. actor-manager, queen-bee.
In subordinative compounds the components are neither structurally nor semantically equal in importance but are based on the domination of the head-member which is, as a rule, the second IÑ, e.g. stone-deaf, age-long. The second IÑ preconditions the part-of-speech meaning of the whole compound.
2. According to the part of speech compounds represent they fall into:
1) compound nouns, e.g. sunbeam, maidservant;
2) compound adjectives, e.g. heart-free, far-reaching;
3) compound pronouns, e.g. somebody, nothing;
4) compound adverbs, e.g. nowhere, inside;
5) compound verbs, e.g. to offset, to bypass, to mass-produce.
From the diachronic point of view many compound verbs of the present-day language are treated not as compound verbs proper but as polymorphic verbs of secondary derivation. They are termed pseudo-compounds and are represented by two groups: a) verbs formed by means of conversion from the stems of compound nouns, e.g. to spotlight (from spotlight); b) verbs formed by back-derivation from the stems of compound nouns, e.g. to babysit (from baby-sitter).
However synchronically compound verbs correspond to the definition of a compound as a word consisting of two free stems and functioning in the sentence as a separate lexical unit. Thus, it seems logical to consider such words as compounds by right of their structure.
3. According to the means of composition compound words are classified into:
1) compounds composed without connecting elements, e.g. heartache, dog-house;
2)compounds composed with the help of a vowel or a consonant as a linking element, e.g. handicraft, speedometer, statesman;
3) compounds composed with the help of linking elements represented by preposition or conjunction stems, e.g. son-in-law, pepper-and-salt.
4. According to the type of bases that form compounds the following classes can be singled out:
1) compounds proper that are formed by joining together bases built on the stems or on the word-forms with or without a linking element, e.g. door-step, street-fighting;
2) derivational compounds that are formed by joining affixes to the bases built on the word-groups or by converting the bases built on the word-groups into other parts of speech, e.g. long-legged —> (long legs) + -ed; a turnkey —> (to turn key) + conversion. Thus, derivational compounds fall into two groups: a) derivational compounds mainly formed with the help of the suffixes -ed and -er applied to bases built, as a rule, on attributive phrases, e.g. narrow-minded, doll-faced, lefthander; b) derivational compounds formed by conversion applied to bases built, as a rule, on three types of phrases — verbal-adverbial phrases (a breakdown), verbal-nominal phrases (a kill-joy) and attributive phrases (a sweet-tooth).