It is connected with strengthening disapproving evaluative connotation which can become pail of the denotative meaning. This process is determined by social and psychological factors. It is mostly observed in the names of persons and reflects disdain of some social group, e.g. wench - daughter -orphan girl - morally bad girl.
Irony means expressing one's meaning by words having an opposite meaning, e.g.. You've got us into a nice mess. A pretty mess you've made of it. These words may develop the opposite ironic meanings in their semantic structures.
Hyperbole is an exaggerated statement not meant to be understood literally but expressing an intensely emotional attitude of the speaker to what he is speaking about. Hyperbole is a characteristic feature of women's speech. Some of the most emphatic words are: absolutely, awfully, terribly, lovely, magnificent, splendid. For example, I haven't seen you for ages. You will be the death of me.
Litotes means expressing the affirmative by the negation of its contrary, e.g. not bad, not half bad. Sometimes there is no negation in the litotes, but a word expressing a smaller degree of some quality is used to express a high degree. Litotes is a characteristic feature of men's speech, e.g. Rather/very -I could do with a cup of tea.
Euphemism means substitution of words with mild connotation for rough, unpleasant, or otherwise unmentionable words. Euphemism is due to social, religious and cultural factors. Taboo is one of these factors. The word lavatory has produced many euphemisms – loo, powder room, washroom, restroom, retiring room, public station, comfort station, ladies', gentlemen's, water-closet (WC), public convenience. Windsor Castle (a comical phrase). Pass away is a euphemism for die, agent for spy, dentures for false teeth.
Euphemisms are particularly common for the processes of reproduction and excretion and for activities, people, and parts of the body involved in these processes. People vary in what they consider to be offensive, and toleration for blunt language also varies from period to period. A euphemism may eventually acquire unpleasant associations and give way to later euphemisms: toilet and lavatory. Themselves euphemisms are frequently replaced by other euphemisms, such as cloakroom. Euphemisms can be used legitimately for politeness and tact, but they are dishonest when they are used to avoid facing unpleasant activities or to conceal and deceive. Dishonest uses are frequent in political and military language: Hitler's plan for the extermination of the Jews was called the final solution; protective custody has been used for imprisonment, industrial action for stickers. police action for war, and armed reconnaissance for bombing.
Genteelism is a kind of euphemism, which means the substitution of a mild or indirect expression for one that might be offensive. Many euphemisms are entirely justified. We use them not only for decency, with reference to bodily parts and functions, but out of generous feelings towards people whom we should otherwise have to call poor, fat, old, crippled, or stupid. But the kind of euphemism here called genteelism is favoured by people who think the frank and obvious word is vulgar. Since the most effective users of the language are seldom afraid of being frank, it is a mistake to try to sound genteel.