Structural types of phraseological units

We shall distinguish set expressions that are nominal phrases:, the worth of the trouble', verbal phrases: put one’s best foot forward; adjectival phrases: as good as gold; red as a cherry; adverbial phrases: from head to foot; prepositional phrases: in the course of; conjunctional phrases: as long as, on the other hand; interjectional phrases: Well, I never!
I. Set expressions functioning like nouns:
N+N: maiden name ‘the surname of a woman before she was married’; family jewels ‘shameful secrets of the CIA’
N’s+N: cat’s paw ‘one who is used for the convenience of a cleverer and stronger person’
Ns'+N: ladies’ man ‘one who makes special effort to charm or please women’.
N+prp+N: the arm of the law; skeleton in the cupboard.
N+A: knight errant (chivalrous man ready to help and protect oppressed and helpless people).
N+and+N: lord and master ‘husband’; all the world and his wife (a more complicated form).
A+N: green room ‘the general reception room of a theatre’ forty winks ‘a short nap’.
N+subordinate clause: ships that pass in the night ‘chance acquaintances’.
II.Set expressions functioning like verbs: V+N: take advantage
V+and+V: pick and choose V+(one’s)+N+(prp): snap ones fingers at V+one+N: give one the bird ‘to fire sb’
V+subordinate clause: see how the land lies ‘to discover the state of affairs’.
III.Set expressions functioning like adjectives: A+and+A: high and mighty
(as)+A+as+N: as old as the hills, as mad as a hatter Set expressions are often used as predicatives but not attributively.
IV.Set expressions functioning like adverbs:
N+N: tooth and nail
prp+N: by heart, of course, against the grain
adv+prp+N: once in a blue moon
prp+N+or+N: by hook or by crook
cj+clause: before one can say Jack Robinson
V.Set expressions functioning like prepositions: prp+N+prp: in consequence of
It should be noted that the type is often but not always characterised by the absence of article. Сf: by reason of, on the ground of.
VI.Set expressions functioning like interjections:
These are often structured as imperative sentences: Bless (one’s) soul! God bless me! Hang it (all)!

Professor Smirnitsky also distinguishes proper phraseological units which, in his classification system, are units with non-figurative meanings, and idioms, that is, units with transferred meanings based on a metaphor.
Professor Koonin out certain inconsistencies in this classification system. First of all, the subdivision into phraseological units (as non-idiomatic units) and idioms contradicts the leading criterion of a phraseological unit suggested by Professor Smirnitsky: it should be idiomatic.