These words are all used to describe particular kinds of attitudes, speech and behaviour. Flippant (with its U.S. colloquial form flip ) and fresh are always unfavourable in connotation. They imply impertinence or lack of respect; flippant also indicates an inappropriate levity in the face of something serious. The three can describe attitudes and actions, but very often relate to speech or writing.

• It is a flippant editorial, not at all in keeping with the importance of its theme; He was fresh when he was a child, and his manners have not improved with age.

Unlike the foregoing words, casual and nonchalant can be neutral or even complimentary in tone. Both words indicate a lack of concern, interest or excitement: a casual air; a nonchalant approach to business problems. Nonchalant , however, may suggest an attempt to be disciplined or detached: Throughout the meeting, he maintained his nonchalant manner, even when the shouting and arguing were at their height.

Smart is close in meaning to flippant and fresh . However, since other senses of smart relate to the possession of intelligence or wisdom, there is sometimes a suggestion of those qualities present even when the word is used in criticism or disparagement. The intelligence and wisdom hinted at are perverted by arrogance or a nasty wit, but they can make the distinction between someone being smart and being fresh : She was a good editor, but she kept making smart remarks to the department head and he finally had to dismiss her. When smart is used in reference to a child, it describes someone who is unpleasantly assertive or forward.

• The little boy was so smart to his mother that she sent him to bed without any tea.