أو تشويهه أي تقبيحه
Or making it appear ugly or repellent.
Tashwīh, in contrast to beautification, selects a comparison intended to evoke aversion or disgust. The classical example likening a pockmarked face to congealed foul material pecked at by birds is meant to transfer a particularly unpleasant imagined texture to the subject.
This is a rhetorical impression, not an objective judgment about a person's worth or appearance. Distinguish explaining degree from disfigurement: the former measures the intensity of a quality, whereas the latter aims to produce a negative emotional response in the audience.