An idiom is a phrase that uses a figurative meaning rather than a literal meaning to convey a point. In other words, one cannot deduce the meaning of an idiomatic phrase by examining the individual words and their meaning. One such expression is "dance around the truth. One does not literally dance or make any physical motion at all. Instead, it means to avoid speaking truthfully outright, or to evade the truth by lying.
The only way to deduce the meaning of an idiomatic expression is to be exposed to it in common conversation. Because the literal meaning of the individual words does not necessarily have any bearing on the actual meaning of the phrase, one cannot simply deduce the meaning by examining the literal definitions of the words; one would reach an inaccurate conclusion using this method. For example, the phrase "dance around the truth" would otherwise imply that one is physically dancing around an object labeled "truth." This is obviously an inaccurate assessment of the phrase, as truth is a concept rather than an object.
Therefore, one must examine the imagery and figurative meaning of the phrase in order to understand it. If someone is dancing, it implies creative movement; if they are doing so around the concept of truth, it means they are approaching the truth but are instead being evasive and circumventing the issue in order to avoid the truth. If someone attempts to dance around it, it is often implied that the truth might implicate that person in a negative way.
To dance around the truth also implies that the speaker is being insincere or secretive. One does not do this when he or she is being forthright and straightforward; instead, it's done when there is something to hide, or some other motivation for avoiding the actuality of a given situation.