And most of them follow not except assumption. Indeed, assumption avails not (10:36)

Almuntakhab Fi Tafsir Alquran Alkarim

Most of them only follow the false suppositions and the incitement arising from the state of their minds and feeling. An opinion offered on insufficient presumptive evidence cannot override the truth nor overrule it; Allah is Alimun (Omniscient) of all that they do

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(10:36) Most of them only follow conjectures; *44 and surely conjecture can be no substitute for truth. Allah is well aware of whatever they do.

And most of them follow not except assumption. Indeed, assumption avails not meaning

*44). Those who, in disregard of God's guidance, invented religions, developed philosophies and prescribed laws to govern human life did not do this with the help of any definite knowledge that they possessed; rather, it would be the result of their conjecture and fancy. Likewise, those who followed their religious and worldly leaders did so not because they fully knew and fully understood all that the latter espoused. Rather, they followed those leaders merely on the gratuitous assumption that whatever was being taught by those great people, and whatever had been recognized as 'right1 by their own forefathers, must indeed be true.
 

And most of them follow not except assumption. Indeed, assumption avails not meaning in Urdu

حقیقت یہ ہے کہ اِن میں سے اکثر لوگ محض قیاس و گمان کے پیچھے چلے جا رہے ہیں، حالاں کہ گمان حق کی ضرورت کو کچھ بھی پُورا نہیں کرتا جو کچھ یہ کر رہے ہیں اللہ اُس کو خوب جانتا ہے