«لَقَدِ اسْتَسْمَنْتَ يَا هَذَا ذَا وَرَمٍ»
You mistook a swollen man for someone robust and well nourished.
Istasmanta concerns judging someone fat or substantial; dhā waram corrects that judgment by revealing swelling. The point is not a medical diagnosis. It is a deliberately sharp comparison between deceptive outward impressiveness and genuine merit.
A flat rendering (“you saw a fat man”) loses the mistake. The verbs “mistook” or “took for” communicate the evaluative error. The critique remains abrasive; translating it as gentle approval would reverse its force.
Translation exercise
Omit “mistook” from the translation. Does the criticism of faulty judgment survive?