Intensify, aggravate, heighten, enhance mean to increase markedly in degree or measure.
Intensify implies a deepening or strengthening of a thing or especially of its characteristic quality.
Aggravate implies a manifest increase in the seriousness of a situation or condition that is already unpleasant or difficult.
Heighten and enhance both imply a lifting or raising; heighten, however, tends to imply a lifting above the ordinary, the trite, or the commonplace, and a consequent increase in sharpness and poignancy, and enhance a lifting above the norm or the average in desirability or attractiveness by the addition of something that increases the value, charm, or prestige of the thing enhanced.