Tim Bowen sheds some light on the origins and definition of the phrase to beat about the bush.
If you beat about the bush, you spend a long time getting to the main point of something for some reason, often because you are embarrassed or reluctant to offend the other person.
The expression appears to have its origins in hunting in medieval times. Rich noblemen who enjoyed the hunt would employ young men to do the dangerous work of flushing animals out of the undergrowth so that the noblemen could kill them. This was often done by beating a wooden board with a stick to make a noise that would frighten the animal. However, the beaters knew that some animals were dangerous and, in particular, wild boar. Often they would be reluctant to enter bushes or areas of dense undergrowth in case they disturbed a boar that would attack them. In such cases, instead of going into the bush, they would beat around it, thus remaining safe but essentially avoiding the main point of their activity.