What is meant by positive deviations from Raoult's Law?

Positive deviation from Raoult's law means that the observed vapor pressure is greater than expected and it occurs when A-B attractions are weaker than the average of the attraction in the pure component of the mixture. For example, a mixture of ethanol and acetone shows a positive deviation from Raoult's law. In case of solutions showing positive deviations, absorption of heat takes place, i.e., ΔmixH has a positive (+) sign.